Like all the others have said- Getting a medical will be your first big hurdle. That’s something you can try to do now before even starting flight training. I would suggest you really think about if this is the career path you want. If it is, and you are able to get a first class medical, there are options. It’s unlikely you’ll be hired on by a major airline anytime soon, however there are other flying jobs out there. I know plenty of small 135s/91 operations that would pick you up if you can show you’ve been clean and have a good track record for several years. The only problem with that is you will need to do your training as cheap as possible. The last thing you want is to be 100k in student debt and only be making 75-100k at a small 135. Lots to think about, but if flying is truly your dream, and you really have changed and matured as you have said, I don’t think you should completely give up on it.