Ahaaaaa now it all makes more sense :)
I was wondering at how odd your post sounded - it was as if you were asking a question which you really weren't even sure about yourself, almost as if it were a whole idea alien to you in the first place.
And it is. Because this isn't coming from you, but from him.
No, from the tone of your posts, I think that you very much should not have children now (that would have been my opinion even if you'd stopped at the post which said you are only 23, by the way). But the rest of it really puts the tin lid on it. DO NOT have a baby because it's what he wants but not necessarily you. Especially at only 23. And especially especially if that person fully intends to continue his life and career exactly the same while delegating most of the childcare to you. That is really really not a good idea.
Overall the picture here isn't great - I know it's only a snapshot but your DH is not exactly coming across well here. One could say it sounds very much like he's got the great career, tick, finished his training, tick, found a wife, got the big mortgage, tick tick... so now it's time for the kiddies to come along. You? Only 23, been with him since you were 18, quite a bit younger, and clearly not yet sure what you want to do with your life, or even whether you really want children. Hmmm.
At 23, I would have said I didn't want children. I certainly wasn't interested in having them or even giving serious thought to whether that was part of my life plan. Because at 23, that's the way it should be - unless you definitely are in the 'I really want children young' camp.
You are clearly not. Do you work? Do you have a career? Do you want one? What are your dreams? Do they include opting to be a stay-at-home-parent in your early 20s? Because that's quite a choice. And not one HE wanted for himself, that's for sure.
I think that you should say to your DH exactly what's come out of this thread. That at 23 you are far too young to be thinking about children yet. Maybe in five years. You want to work out exactly what you want from life, career, everything. You have plently of time. And because he is the man, so does he. If he wanted to make sure that he became a father at 30... he should have picked a partner nearer his own age, for a start. :)
I would be very interested to hear his response to that. Because if he's a man worth having, it should be an enthusiastic yes, it has to be right for both of us, it's only fair you get your stab at developing a career too, like me, now that we are starting to be financially comfortable, yep I wouldn't have wanted babies at 23 either.
If you get anger, disappointment, pressure, manipulation, and the attitude that you should be falling in with His Master Plan... then it could be time for a serious think.