John... You may be young, but your W is even younger with a small child involved. She is vulnerable in many ways you are not (financially, negotiating skills).
It sounds like you both have a lot of growing up to do, but that you also have more potential for happiness than many of us here. As you' ve seen with Cat Lady, the baggage gets heavier as you get holder... Young love can be the best love if you can figure it out.
Put the work into yourself and the R if she's open to it. Don't crowd her, and realize she's trying not to feel so vulnerable by being more independent.
Good Luck!!
However it goes down, do be the man she will respect as the father of her child, no matter what.