How do i get less nervous about doing things in mass?

Everyone gets nervous their first time(s), talk about your concerns, practice well and make sure you pray and leave your concerns in the hands of God, trust in Him when you do whatever it is your supposed to be doing.

The best way to gain confidence though (as well as prayer) is practice, after you have done it a few times you'll get less and less nervous.

I don't understand you question? What is it that makes you nervous about attending Mass? Being in the presence of our Lord Jesus Christ, should give you peace to your soul. Say your prayers and ask forgiveness for your sins. If you are in the state of Grace you may received the Holy Eucharist.

However, if you are not in the State of Grace ( committed mortal sins ) and you consume the Holy Eucharist, then that will make anyone nervous. No one should consume the Holy Eucharist in the state of mortal sins. If a person does consume the Eucharist in the state of mortal sin, that person commits a sacrilege and it brings self condemnation to the person's soul.

The Church offers the Sacrament of Reconciliation for all Catholics, who are in serious sins. It is a good practice to go to confession regularly.

Take care and may God Bless you.