I like this kid but I kinda get really shy around him

First off make sure you realize guys are incredibly sad creatures. Especially in high school. If you're ignoring him outside of class because you're too shy to say or do anything, that will most likely cause him to think you don't like him, or you aren't interested in him at all. Your shyness has the possibility of giving off the wrong impression to him.

The most important thing you can do now is if you're texting and calling him is that you try and overcome your shyness by talking to him in person more. Hang out with him during break, or lunch, or go to a movie together (movies are great for high schoolers). If he's trying to make moves on you and you're backing away because you're shy he might think you're trying to ignore him or push him away. So be sure he knows you ARE interested, you're just new to relationships and a bit nervous.

You've got 4 years left of high school, and this will probably be one of MANY relationships or almost-relationships you're going to have. Use this opportunity to get your feet wet in the dating arena.

I wish you the best of luck and feel free to ask any more questions.