This guy has not even known me for more than two days yet he says he loves me?

Okay so I was on Youtube, and I actually decided to log on. I never felt it was a good idea to go on my account on youtube, because I don't usually go on youtube. I got this message from this guy on the 23 of this month, saying that he wants me to be his boyfriend. I mean is there anything more anonymous then youtube? I mean he has no idea who I am, what I'm like, yet he wants me as his boyfriend? So I was trying to be nice, and all, and he's 13!! I'm like yeah that's not going to work I'm 16 and about to go off to Germany, I just am also too busy. Plus I don't know you! He gets all deffensive, and says he feels like crying cause he says he loves me, which just gets on my freaking nerves!! I mean what's up with every guy I have been dating these past weeks being absolutely obsessed with me!! This guy Tyler I dated a couple Saturday's ago is going all crazy blowing up my phone, saying he misses me, he calls me at work, and it's like wtf! We had sex ( but I don't think I really want more than that) Then I went on a date with this guy Kale, and we had sex, and I think I kind of like him too, and he gives me space, but also gets a little clingy too. I cannot stand clingyness. I feel choked. i am getting so sick of people taking everything so personally, if I am not texting you, don't get all "did i do something to make you upset?" no i'm just effing busy either at my piano, guitar, or at work, the dance studio, or at a vocal lesson. So I have more then one question. What do I do in the situation of the 13 year old boy, and how do I get all these people stop being all clingy!? Tausend danke, es ist sehr lang, und fur das es tut mir leid. (Thousand thank you's, it is very long, and for that I am sorry)