Totally disagree. People are way more accepting of young parents these days. The old 'I'll be enjoying myself in my 40's when all my friends are changing nappies' attitude is rife. I think there's a lot more stigma towards older parents these days.
People definitely aren't more accepting of 19 year old parents than 49. They really aren't.
19: kids having kids, you've ruined your life, can't have a career, can't have education, no free time, ruined your youth, your relationship will fail, you don't own a home, I spent my 20s travelling how sad for you that you can't, ^
49: everything worked out fine for me, it's your business, nobody should judge you, my auntie had a baby at 47 and she's still alive 50 years later, ooh how lovely^
Saying 'they'll be out of nappies' is hardly an insulting comment to a 40 year of first time parent who is doing things the 'normal' way as their peers. It's it a bit like people saying treat they feel straight is the minority.
As I say, I only bring it up because it's so stark on MN which is anon so you get a real idea. If 19 is too young, then 49 is probably too old.