First giving false information to the police is NOT forgery. Forgery is generally a felony. Giving false information to the police is generally a misdemeanor. If you created a state ID or driver's license and presented it to the police, that is another matter, and most places is a felony. But it is virtually impossible to forge drivers licenses these days and once they sent in the info to DMV they would know it is fake. Rather pointless to commit a felony you will be busted for the first time the DL is used.

They will likely arrest you on the spot. However, they might give you a reasonable bond, even personal recognizance. The problem is, if you are taken into custody, they will see you are on probation and notify the probation officer. A bond will likely be set for that too, or there might be no bond.

You screwed your friend and you were screwed back. The money is only part of it, there are points lost, insurance costs go up, and there are court costs and maybe other things in addition to the fines themselves.

You will get arrested. The odds are it will be at a really bad time. You can at least have some control over the situation, by making whatever arrangements you can to pay bail, secure you living situation and so forth, and then go turn yourself in.

Jails and prisons are so crowded, that for a couple of non-violent offenses, the court and probation officer might both give you are break and not incarcerate you.