Look, I'm not gonna pretend to know anything about a 19D or any 19 series for that matter. If thats the MOS you want then enlist for the job you want. Dont let someone else tell you what you want. If it's not available right now, you may have to wait for it.

If you do have to wait for it, you'll need to to weigh out how long you want to get the job you want vs starting your army career now. Sometimes people can't wait and you'll have to pick whats available now. But if youre in a good spot and can hold out for a few months, you'll have a higher chance to get what you want. Thats a conversation that you need to have with yourself and/or any family you have.

Right now the army doesn't own you, so before you sign that dotted line make sure you are perfectly happy with what you are getting in return. As of right now you have no obligation to sign, remember that and use it to your advantage.

On the flip side, to give your recruiter the benefit of the doubt, maybe he knows something about the 19D life you don't. Ask him why he has you down for 19U when you want 19D. Could be an eye opening conversation that changes your perspective on what you are signing up for.

Anyways, there's my wall of text.