Picky Eater

So, Noah's doctor told us at his 15 month appointment that we really needed to force the issue and make him switch to regular food. Yes, Noah still wants his baby food. We have tried 3rd foods, Graduates, mashed potatoes, bean, etc. I've listened to advice from everyone I know. He'll eat pancakes, biscuits, toast, and peanut butter sandwiches without a fight. He cries through almost every bite when we feed him anything else. It is sooo frustrating. Everyone says that as soon as their baby tried regular food, they didn't want baby food. Not mine. Did we wait too long or is he just stubborn? I'm leaning towards stubborn.