16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified. 17 But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid. 18 For if I build again the things which I destroyed, I make myself a transgressor. 19 For I through the law am dead to the law, that I might live unto God. 20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.

That "of " is a little word and I believe the Greek backs me up here. Our faith at the new birth is Christ's faith given to us, not our faith. A faith we must grow and develop with the Holy Spirit working in us.

Then I checked its derivative 911.
ba¿ptw baptoœ; a primary verb; to whelm, i.e. cover wholly with a fluid; in the New Testament only in a qualified or special sense, i.e. (literally) to moisten (a part of one’s person), or (by implication) to stain (as with dye): — dip.

"literally to moisten a part of one's body" Why is full immersion considered its only possible meaning?

http://www.fivesolas.com/sprinkle.htm

Just a thought from a well known modern theologian "The baptizer John himself therefore declared to his converts: "I indeed baptize you with water" -- not under it! Matthew 3:11a and Mark 1:8a and John 1:26a & 1:31b & 1:33a. Throughout, the Greek has en, meaning "with" -- and not hupo(katoo), meaning "under(neath).""

Another issue - who led you to believe that Presbyterians believe in baptismal regeneration? in any literature I've read it is a sign and seal of the covenant as was the rainbow and circumcision and the communion table.