Christianity ?

No, God cannot forgive all sins.  There is no forgiveness for murder nor the sin against the Holy Ghost, but there is eventual redemption for murderers.  It's never too late, and you need never lose hope, until we murder, sin against the Holy Ghost, or die in our sins (real repentance takes time and effort).

Of course God can forgive all sins - not only "can" do so, but strongly desires to do so. While the Roman soldiers were nailing Jesus to the cross, He cried out to His Father in Heaven, asking Him to forgive them for what they were doing.

Do you believe that God is all powerful? He created the earth, humans, animals, etc. So, knowing that, how could forgiveness of sins be too difficult for Him? Think about King David. He committed murder and adultery. Those are pretty major sins. But when he sincerely repented, God forgave him. Prayer helps. There is nothing wrong with asking God for help with this. 

Come now, and let us reason together, saith the LORD: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.

Isaiah 1:18

The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.

John 1:29

All sin was what Jesus took upon Himself. Every sin committed by every person on earth who ever lived, or will live.

There is but one sin, which is not a sin of action or failure to act, that needs to be dealt with; the sin of unbelief.John 16:7  Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.

8  And when he is come, he will reprove the world of sin, and of righteousness, and of judgment:

9  Of sin, because they believe not on me;It now comes down to belief / faith, or unbelief. His written Word says He took away all sin. Why would you be the exception?

Yes. No matter what you have done, Jesus Christ paid for it on the cross! The moment you believe in Jesus Christ alone as Savior, ALL of your sins (past, present and future) are completely forgiven (Acts 10:43).

The truth is that death leads to heaven or hell, and the only way to heaven is through faith in Jesus Christ.

The Bible is very clear that no one can earn their way to heaven since good works do not pay for sins. See Gal. 2:16, Rom. 3:23-28, 4:4-5, Eph. 2:8-9, Tit. 3:5. The only way to heaven is by believing in Jesus for His free gift of eternal life. Jesus shed His blood on the cross as the full payment for our sins. He did all the work; all He requires of us is that we believe in Him. Once you believe in Jesus Christ to save you, you are secure forever!

Because we have all sinned against a perfectly holy and righteous God, we all deserve eternal separation from God in hell (Rom. 6:23). However, God loves us so much that He sent His only Son Jesus to die on the cross as our Substitute so we don't have to go to hell. Christ died for our sins, was buried, and rose from the grave three days later (1 Cor. 15:3-4). He gives eternal life freely to anyone who simply believes in Him for it. No one can be saved by doing good works. Salvation is by grace alone through faith alone in Christ alone (Eph. 2:8-9).

"Verily, verily, I say unto you, He that believeth on me hath everlasting life" (John 6:47).

You are very much a candidate for the saving grace og the Lord Jesus Christ because of your regrets about your past.

You see, when Jesus hung on the cross, the sin of the whole world was poured out on Him.

When you believe on the Lord Jesus as your Saviour, all your sin being past, present, and future is all forgiven and at the point of belief, you pass from death into life because at that moment, you are forever sealed by the Lord and have eternal life at that moment.

It isn't possible for you to have ever committed the unpardonable sin as the circumstances under which it was committed in early New Testament times do not exist since the passing of the apostolic age. 

In order for this sin to be committed there had to firstly be a two-fold heavenly witness and the working of a miracle. Such a miracle had to be something which was well beyond the ability of man such as raising the dead, making the blind to see, etc., And on witnessing such a miracle, knowing that it was the work of the Holy Spirit (Holy Ghost) then to openly, knowingly, deliberately  publicly accuse the worker of the miracle to be the work of Satan (The Devil).

Such was the case when Jesus was casting out demons from a man who was both blind and dumb. When the Lord healed Him, the Pharisees who hated the Lord, knowingly, publicly stated before all present that the Lord had worked the miracle by the power of Satan hence, they were guilty of blasphemy against the Holy Ghost.

You have nothing at all to concern yourself as to not being forgiven. You have the Lord's total assurance that you wil beforgiven totally once you believe on Jesus as your Saviour.

Don't let Satan play with your mind as he constantly attacks believers with his favourite weapon, DOUBT. 

Rest assured in the total confidence of the Lord's promise for you.

God Bless.

Yes it is true,but it take action on your part. Acknowledge your sin as a violation of God’s standards. While others may have been hurt by what you did, you must first recognize that your sin is an offense against God.​—Psalm 51:​1, 4; Acts 24:16.

Confess to God in prayer.​—Psalm 32:5; 1 John 1:9.

Feel a deep sorrow for your sin. This “sadness in a godly way” leads to repentance, or a change of heart. (2 Corinthians 7:​10) It includes regret over the wrong steps that led to the sin.​—Matthew 5:​27, 28.

Change your course of action, that is, “turn around.” (Acts 3:​19) This could mean that you avoid repeating a single wrong action or practice, or it could mean that you may have to change your whole way of thinking and acting.​—Ephesians 4:​23, 24.

Take steps to right the wrong or to repair the damage done. (Matthew 5:​23, 24; 2 Corinthians 7:​11) Apologize to those who suffered because of what you did or failed to do, and make restitution to the extent possible.​—Luke 19:​7-​10.

Ask God in prayer for forgiveness on the basis of the ransom of Jesus. (Ephesians 1:7) For your prayer to be answered, you must forgive those who have sinned against you.​—Matthew 6:​14, 15.

If your sin is serious, speak to someone who is qualified to provide the spiritual help you need and who can pray in your behalf.​—James 5:​14-​16.

ask god to help you with all this

Yes, that's Christianity.  God will forgive all those who sincerely repent of their sins -- with the exception of blasphemy against the Holy Spirit, which is unforgivable.

It's not only true that he can, he already has forgiven everybody, for everything.  You're invited to step into that reality, friend.