Rutherford, if you are a minor then you have to do what your parents or guardians say.
If you are an adult, then you must make the decision on your own. I understand not wanting to upset your aunt though, if you are dependent on her to give you a place to live.
Many great saints had families who didn’t like their faith practice and tried to stop them from becoming Catholics or going to Mass. But if they had the strong desire to be Catholic, that generally won out. They would sneak to church or do whatever they had to do to be able to practice the faith because they didn’t want to be away from Jesus. Sometimes they had to move out and find someplace else to live.
I think that planning for you to be the next priest is a little bit of a crazy statement. You aren’t even a Catholic yet. You can tell your aunt that the person who said that is a bit crazy and nothing of the sort is going on.
I would suggest speaking to your priest to see if he has advice on how best to handle this. One important thing is that the priest is part of your culture. Most of us posting here are far away and we don’t know your culture or your family the way someone right there would know. So maybe the priest would give better advice.
I will pray for you and I hope you are still able to become a Catholic and practice your faith. The Lord does seem to have chosen you to be a Catholic man (although to say he has chosen you to be a priest is too early to say).
God bless.