I had my first boy at 22, he was planned and I was concerned that people were gonna think it was a silly decision (I was in my first year of teaching) --- but everyone was really supportive.
DH and I had been married since I was 21 and he was 28. So I finished my first year of teaching heavily pregnant, then amazingly got offered a part-time job when Harry was a few months old. It meant I've been able to do another year and half of teaching, and in the process get full registration (it's 2 years in total). I'm finishing up work at Christmas for maternity leave for our next bubs due in March.
So I guess what I'm trying to say is, although it might not "make sense" to other people, and even when it's not planned - things really do work out. It's hard at times but you CAN fit in what you want/need to do, as well as have an awesome family life. You do what you gotta do to make it work. Don't listen to those people who put you down, they have no idea. It's WONDERFUL being a young mum, I love it.
Oh and this reminds me - my friend was nannying (she's my age) and was at the shops with the wee 2 year old girl. They walked past this old man so she smiled and said hello - he just looked at her and said "young mum" in this awful tone. I couldn't believe it! So yeah in situations like that, you just smile and say "yeah and it's great" It's so ironic, cos back in his day, most women had babies before they were 20, or early 20's at least!!
And the whole Maori/Pakeha thing - I'm Pakeha, DH is a small part Maori (looks Pakeha but Maori culture is part of his heritage IYKWIM). Both our families and all our friends were stoked.