Hi, Cladre60 and welcome !
I was in a similar place sizewise and mentally as i imagine you are when i began, around the same age too.
The best way to see how long it will take to see gains is to start

Your goals are attainable, you just have to be consistent with your routine.
The only downside is that once you get to 7,5 bpel you will want more

And screw adult entertainment, yes there are some monstercocks in adult entertainment, but so much is just camera angles and shit…There’s a great thread in mental penis enlargement sub forum “ Wan’t a adult entertainment star dick ? Do a adult entertainment star film, check it out. You might surprise yourself.