Why does baptism need water?

The word baptize literally means "plunge" into water. Water is the physical part of it. You may as well ask why is there bread, and wine at Mass. Yes, the Holy Spirit is transferred in these things; that's what a sacrament is. But, the physical thing also needs to be there. For baptism, that means water.

Why baptism with water? What is the point of the action?

Imagine jumping into a pool of mud and call it bathing, cleaning of oneself. While the intention and desire is there, the action does not reflect washing, removing of dirt. Baptism is a sacrament, an outward sign of an inward grace. The act needs to reflect what is happening within. Of course not to mention because Christ himself was baptized with water, so too we shall follow.

Where is my accepting if I had no decision making capabilities during Infant baptism?

Now this is the beauty of the Catholic faith.

CCC1231"...By its very nature infant Baptism requires a post-baptismal catechumenate. Not only is there a need for instruction after Baptism, but also for the necessary flowering of baptismal grace in personal growth. The catechism has its proper place here."

CCC1253 "Baptism is the sacrament of faith.But faith needs the community of believers. It is only within the faith of the Church that each of the faithful can believe. The faith required for Baptism is not a perfect and mature faith, but a beginning that is called to (1123, 168) develop."

CCC1263"By Baptism all sins are forgiven, original sin and all personal sins, as well as all punishment for sin.66 In those who have been reborn nothing remains that would impede their entry into the Kingdom of God, neither Adam’s sin, nor personal sin, nor the consequences of sin, the gravest of which is separation from God. (977, 1425)"

But wasn't he in a river? Specifically, the river Jordan?

As I recall the water symbolizes, in some groups, the burial and resurrection. This is considerably easier to do with water than dirt, concrete, and other materials.

"John answered them all, “I baptize you with water. But one who is more powerful than I will come, the straps of whose sandals I am not worthy to untie. He will baptize you with the Holy Spirit and fire."

Luke 3:16

“I baptize you with water for repentance. But after me comes one who is more powerful than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire."

Matthew 3:11

Water means to be submersed in. When Jesus came out of the water, heaven opened. It's metaphor for being initiated into the light.

Why does baptism need fire?

Because that's just what Baptism is. That's how Jesus made it.

"Truly, truly, I say to you, unless one is born of water and the Spirit he cannot enter into the kingdom of God." -John 3:5

Just because a lack of opportunity to be baptized doesn't damn doesn't mean baptism isn't the method God normally desires to use.

You accepted it (confirmed is better word) at your Confirmation. But Baptism is God coming to us, it's really doesn't matter if you understand it at the time. It's God's work.

Yes, you must be born again by the blood and the water. Blood ( the atonement of Christ) Water ( baptism by immersion.)

We are surrounded by water in our mothers' womb. When we are born, we are leaving that watered enviroment. Water is needed to symbolize our being born again.