Why is this guy so scared to say he likes me or somebody else?

I feel you're not going to like my answer but it's he best I can give.
Let's look at it:
-(Age:Under 18)
-"I'm (16) and he is (18)"
-"I asked him if he liked anyone and he said not really. "
-"he made it very clear it wasn't me"
-"After I told him, he was like your to young "
- then this question: link

-My opinion:
I understand what you're feeling but you're going way to fast for your age, for him and for his feelings towards you: it's not because he likes you as a friend or as a "little sister" that he wants to get into a relationship with a girl 2 years younger than he is. Since he's 18 and you 16 he might even end up in jail (statutory rape), depending on the state you live in.

Wait two years: it will be legal then, you'll be more secure about your feelings and aims and he will accept you more as an equal instead of considering you as a nice young friend or some sort of "little sister".

(I've been in his position a few times and had to say "no" or pretend not to understand which direction the girls were pushing. Yes, they were angry at me when they got the answer or absence of answer. And , yes, I felt honestly sorry for them, because I liked them. It was even because I liked them that I abstained)

I hope you understand my reasoning.