Worried that my teenage son is too immature and will get bullied in high school. Am I making a big deal out of nothing?

I have three kids. My 13 year old is the one I am mildly concerned about. He will be 14 in June and will start high school in September.He is an awesome kid, but he is pretty immature for his age as far as interest go. He'd rather dig up rocks up in the yard than play a game of touch football with his brother and the boys in the neighborhood. He'd rather play Minecraft than text his friends. His brother had a couple of friends over last night to watch the Final Four (college basketball) and my younger son stayed in his room to watch cartoons. We go shopping for clothes and my older son picks out whatever is in style and the younger one is still looking at shirts with cartoons on them.I am not trying to compare the boys, but I wanted to give you an idea of what I meant by "immature." They are 12 months and 2 weeks apart, so it's easy to see how different they are as far as maturity is concerned. It's also very easy to see when I compare him to other boys in his grade. They are all into more mature things and it seems like he is getting left behind a bit.I just worry about him in high school. Should I encourage him to expand his wardrobe a little bit to include more age appropriate clothing? I don't want to discourage him from watching cartoons, but should I try to get him to stop talking about it so much? I don't want him to feel like he has to hide who he is, but I also don't want him to get made fun of either. I'm a single mom and I don't really have someone to guide me on life as a teenage boy. I just know that my older son says that his brother will be picked on in high school if he continues to act childish. via /r/Parenting http://ift.tt/2oqV5MT