I need help with this relationship?

[Amanda]

Ok so this is really messed up I know, but I meet this kid on minecraft.. He really won't leave me alone he said stuff like "Hey lets go out!." Every 3 seconds. I tried telling him no and said that he didn't know me and for all I know he could be a 7 year old or a really old pevert. He wanted to prove it to me that he was really a 14 year old boy, so I let him. I looked up
his insagram and saw him I think he was like an 8/10. The he started telling me stuff like " Aye I'm a sexy beast right". "I said yea ok" just to shut t him up and now he thinks we're GF and BF?!? (I realize now I could have blocked him and left the game but I need help now!) I want to tell him I can't date him I so need a "story". I'm to soft to block him on Instagram and I LOVE THAT MINECRAFT SEVER! So I just need to tell him off nicely so that we can still be friends? Because I really can't date yet even... I'm 14 plus my mom stocks my Instagram too so if she saw that I was "going out" with someone I didn't know she'd kill me. Please help I need your help. How do I put this kid down nicely because he seems nice?