How soon is too soon & how young is too young?

Roberta
   Hey guys. So bare with me here, because this is kind of a long story, and please don't be quick to judge.
   So I'm currently 13, turning 14 in a week (I identify as gay, but as you will soon learn, one person does not change your entire identity). I've been in this inpatient program for teens with mental illness for 2 months now (I've been diagnosed with anxiety, severe depression, & PTSD). And there's this guy named Ty, he's a year and a half older than me (15) (& he just recently started to identify as ftm) and I've liked him for the majority of the time I've been here. Going on 2 weeks ago I told him I really liked him, and it turns out he liked me back. So we've been talking and acting like a couple 24/7 since then, & he just officially asked me out last night since he just got discharged. 
   He is a very sexual person, which I am a okay with, because I am too. He however has had a hell of a lot more experience than me. He's been in sexual relationships before, meanwhile I'd never even kissed anyone, having never found anyone like him before. So it should be interesting at first, but I doubt it'll take me long to get the hang of stuff.
   But since we've already been behaving like a couple for a bit, we definitely jumped right into things. Tonight was amazing, we haven't seen each other yet since he got discharged not even 12 hours ago but we're hanging out tomorrow night. So we basically just talked (texted, facetimed, snapchatted, you get the gist) all night. At one point he told me he was horny & I was to an extreme amount myself already & when I told him she started sending me all these photos of him (keep in mind he isn't transitioned at all in any physical way, thus this initial sexual attraction in the first place) and asking if it was helping, basically being the perverted butthole he is knowing I was probably getting off (which I couldn't help but to, I was literally about to explode doing absolutely nothing) & he was enjoying the hell out of it. 
   So he's said before he even asked me out that I probably wouldn't want to be with someone as sexual as he is, knowing that he would want the sexual aspect of any possible relationship as well, which for some reason he didn't think I would be okay with, although I told him I was, but to say the least he was sure as hell pleasantly surprised.
   I'm aware jumping into any type of sexual thing this early in a relationship & even at my age may sound kind of crazy, but it's something I know we both want and are ready for. We know all the precautionary measures there are to be taken, & we don't have to worry about the whole birth control thing. I'm head over heals in love with him. So I'm just here looking for advice, what anyone here thinks would be the right way to go about anything right now. Thanks.