Yep, the engine is flooded. You are seeing either a backfire or a hydrolic lock.

Get an instructor ASAP. Part of the instructors job is to teach you how to make the engines run well. I've had several students show up with out having a clue how to start their engine, and that's fine. In fact, I almost prefer it, less chance of them damaging the engine or hurting themselves or someone else.

If you are going to start the engine yourself, make sure the engine is well secured. If it's in the plane, that means fixing the plane with a tie-down of some sort so it can't roll forwards. If you're using a bench mount, make sure it's up to the job.