Quite lot of people on here had a mortgage at 17-20 years old. 
That would have been my idea of hell at that age.
Having kids AND being tied down with a mortgage.
No thanks. In my late teens, I was too busy enjoying my life, and partying, and going on holidays with my friends, and being excited about not knowing what I'd be doing this time next year.
In my opinion, there's more to life than tying yourself down (with kids and a mortgage,) when you are barely out of your childhood.
Like a few other posters, I am amazed that people even managed to GET a mortgage in their teens!
I am sure I will be accused of 'judging,' but if you're happy with your life choices, why are you offended by what others say or think? Why do you care what other people think?