If you blew your crush off twice, you should apologize as this would be the right and polite thing to do.
This being said, you really do need to figure out what your true feelings are. This has to be determined before taking any further steps with this crush.
You have to ask yourself a very important question that requires some time to ponder.
It is very possible that you are falling into a relationship. In fact, simply wondering about whether you are falling into a relationship is often an indication that you are.