Welcome to the Church and Catholic Answers!
I am so glad you are still here, that you didn’t take your life.
God can actually make the greatest good come even out of greatest evil. Recall that St. Paul used to, himself, be a huge persecutor of Christians. He went from Paul the persecutor to Paul, the persecuted!
Later, he ended up undergoing stoning, being left for dead. I think he was shipwrecked was it 3 times? He was finally martyred. He was responsible in large part for helping bring the word to the gentiles.
Have you ever heard of St. Cyprian (and St. Justina)? He used to be one of the Devil’s right hand men. He later turned from this path of sin and became a saint, in his own right.
What will the priest think? Well, it varies, surely, from priest to priest. However, if he judges you, when you are trying to change you life around, he would not be in the right profession. No, a priest is to absolve you, not to throw you out or anything like that.
People say that priests, unless you get a new one, have generally heard it all, that there’s normally little you can say that would shock them.
I once heard a priest on a Catholic radio program who talked about people who hadn’t been to confession, say, in 30 years. He said those were actually his favorite cases. He called them “the big fish”! He liked it when people who really needed the sacrament most came.
Archbishop Fulton used to say hearing nun’s confessions was like being stoned to death, using popcorn!
You’re new to the faith, but there is also St. Faustina who was with the Divine Mercy. I think she once doubted Christ’s mercy, and Christ responded that her doubt in his mercy was actually much more painful than her original sin!
Christ told Faustina to tell people that the greatest sinners have the greatest right to his mercy. He also said that pride was one of the major obstacles in people coming to him.
I am very glad you have worked so hard to turn your life around. I think the priest would see that, but what’s important in the end isn’t what even that priest thinks but what God thinks. I would think God would have to be pleased at your efforts.
I would like to commend you and encourage you to do it however you feel most comfortable. If possible, maybe you can find a way to confess, anonymously, behind a screen. It might be easier for you to be able to speak frankly.
Congratulations on turning your life around. It’s no easy thing to do.
If it’d be easier, you could also go to a different city. That’s the other way.
The main thing is to go. Good luck in your first confession, and God bless.