Older guy, too dangerous?

I'm usually a very normal-lfe person. I don't go out of my way to get attention, I'm not the hugely social type in fairness, I'm just not into a lot of high school stuff, but I cl most people in school as a friend. since about november ive known a guy whos 21, i turned 16 recently. im used to guys my age and most guys i've known for a long time, but im not really used to new guys let alone older ones and ones that act like this guy. one minute he really seems like hes coming onto me, but then i think im being stupid because he'll say something weird. he'll do weird things to like throw stones at my window to get me to talk at night, and im always afraid my mum or dad will hear. i've told him but he just laughs. he's kinda scared me at times, one time he said 'i have a history you know' but then didn't tell me what he meant because 'wheres the fun in that'. on one hand i really like him, i find something hugely interesting about him, but on the other, i know my dad especially wouldn't approve, and i dont even know what he wants eventually, hes 21 after all and im not exactly experienced with relationships to that level. has anyone been in a similar situation? am i being stupid to find him so interesting? im really half-ranting here but i really would like any advice you might have.