To tell you the truth, they aren't that aggressive at all. Their feeding response is incredible, but once you get them out of the cage, they can be very manageable. I have never heard mine hiss ever, and I have only been biten once, and that was just my mistake.
But I agree with Denial, given your age, I would wait on SD retics and get a ball python. Trust me if SD retics are something you truely want then when the time comes you're still going to want it just as bad, plus they'll be more affordable. I wanted to get my first snake when I was 13, but my folks stepped in. As a result, I got my first on my 18th B-day, and I thank them for that, I wasn't prepared for one at that time. Also if you just want a low maintence snake, ball pythons are a better choice imho.
But then again, that is just my![]()