feeding baby solids!

My son is developmentally at the stage where he should be able to eat 2nd and 3rd foods along with things like Cheerios, Gerber Puffs, and Crunchies. However, often when he eats things that are thick he chokes and then vomits. I don't know if He isn't ready or there is something wrong. He does really good some times. He clearly wants to eat these things. Also he only has two teeth, the bottom front ones. He does try to mash things with his jaws. I just hope nothing is wrong.