Please note that I only put a question mark due to the rules, but I am in need of some new perspectives.
I 21F (will be 22 soon) have been with my boyfriend (19M but about to be 20) for a while. We we're together for 2 1/2 years before I ultimately broke it off after having our daughter when I was 18. (Mental health, PPD, sole parenting, etc. lead to our break up). We split for just over a year and rekindled our relationship last November. Our relationship feels like it picked up right where we left it but a million times better to me. I've started asking to get engaged since we, y'know, already have a child and I'm head over heels in love with him. (I have been since the day we met.) He keeps brushing it off saying things like, "I'm broke." "You're not getting a ring from *cheap places I've seen nice quality rings*." and tonight it was "Because..." I pushed him for a reason why and he said, "I want to wait till we're set." Okay, that makes sense, but I don't believe that's his reason. Before he said that, he said his usual stuff he says when he's wanting to avoid topics. Avoiding conversations on serious topics is a bad habit of his. I feel like I'm talking to a brick wall most times. I just want the truth, but I can't get it. I can accept a no just fine. What I can't accept is not knowing if it's me that's the issue, something with our break up, or whatever else. I'm mentally distraught over it and have tried to communicate. I'm not asking to go get hitched right away. Just to take our relationship a step further. We already have a child that I'd argue is a bigger commitment than a ring and title. I'm not sure when "set" is, After I finish nursing school? We he goes back to the military in who knows how long?? A part of me feels like he just don't want to because I'll expect a post or for him to acknowledge it to others, (He RARELY posts me and has never posted his daughter because "I don't post") and I know posting is not a big thing, but when it comes to events like engagements or birthdays I feel as it should be. Another part of me feels like maybe he misses the girl he dated for 8 months after we broke up. Or maybe it's simply because we broke up. I don't know, but I am very hurt and confused. I can't discuss this with anyone in my personal life, because they'll just tell me to leave. I don't want to leave again.
How do I go about approaching a deeper discussion? Do you think I'm over reacting or too impatient?
TL;DR: Boyfriend doesn't want to get engaged yet because we're not "set" even though we have a 2 year old child and have been together for a while. He keeps making excuses when I push for a deeper discussion. I'm struggling with how I should go about this situation.