Odd as this may sound, I wonder if perhaps he is worried that you following your dream will result in the relationship inevitably coming to an end. Having children with you might be his idea of keeping you two together. It's rare, but there also have been instances I know of where the man used children as a form of control to keep his spouse/girlfriend from leaving him.
Dragonhermit is correct. This isn't rare where I'm from (poor southern town.) men don't have anything to own, so they try to "own" the woman with children.
If he is willing to wait until you guys are more comfortable...I'd say no. Lots of people know they want kids even when they are very young. you should have a real conversation with him about both of you guy's life goals and see if you are on the same page.
Yes, be worried. He's a control-freak for insisting that you have kids so young, especially when he *knows* you have stuff to do. Get away from him. Focus on your dreams.
Follow your dream. In the mean time, he needs to set some goals so he can support his kids. Get married. Then have kids.
You need to fear any man who wants kids and yet has no stable accomplishments under his belt.
And beware. It's SO easy for a guy to split and run away after the kid is born.
Follow your dreams and find a successful man whose capable of comfortably caring for the kids he'd like.
He thinks his dreams are more important than yours and doesn’t care that your children will not be happy knowing mommy is not at her happiest.
Just let him know that you love that he loves you but happiness is first and foremost with you.