Does he like me? Please HELP!!

Hi guys!
So I have a problem concerning a boy that I have known from the age of 5... we (or at least I) have never had romantic interest in each other. But that seems to have changed! We are both 16 but he is mentally a adult, and already working on his own business. We both attend the same church, youth group ect. But more recently he has started helping my dad in his handyman work, and finding reasons to stop by our house. He is from a family where it isn't uncommon to marry at 19 or 20. So here is my observations and dilemma:
1. He has mentioned many times (in my presence) about "when I get married".
2. At youth group this summer he has started a common routine of lifting the pool float I am occupying and dumping me out of it only to catch me.
3. He methodically ignores me, and suddenly will make some comment about me. (often a comment about my ways or looks)
4. He frequently "checks in" on my age.
Over all I have a strange feeling like he is biding his time until I'm old enough to propose too. I think he is handsome (in his own way) but am not sure what to make of this behavior. Because he never treats other girls this way!
Thanks!
Ginger
P.S. He has also gotten semi aggressive with my friend (male) who wants to date me... and very protective of me in general.