Oh, its a tricky one. To an extent, I can see @breaker's point.
Outcomes for the DCs of unmarried teenage mothers are lower than average across the board and I do feel sorry for them.
Added to this, the mother herself gets no chance to explore both herself and the world before the weight of responsibility hits and this is a shame too.
I do understand the argument that you can do your 'living' once the DC have left home, but it just isn't the same IMO.
That said, I am making an assumption here that this is a situation of 2 x accidental pregnancies (poss with 2 different dads?).
If I am being honest, I would judge this situation differently from that in which a couple married at 18, had 2 (planned) DCs before age 20 and were still together.
Do you want to tell us some more about your situation OP? Are you considering your options in an unplanned pregnancy, or do you already have the 2 x DC?