Gotta laugh at the people who hear something they don't like, and instantly accuse the poster who says it of 'talking crap.' Great argument. Says a lot more about them tbh.
FWIW, I agree with pretty much everything Margaret Cavendish says. And you would have to be very naive to think if you start having children at 19-20, that your life is going to be easy, that you're going to do a degree in your mid 20's, that you will sail into an amazing career, and have a wonderful fruitful life with a 6 figure salary, backpacking around the world with the kids and your nanny in your late 20's!
Get real!
Having kids before 20 is just setting yourself up for a life of drudgery, putting any higher education on hold, shelving any career for a long time, (maybe even for good,) having to constantly watch the pennies, rarely travelling anywhere, and having to always put your kids before ANYthing you ever do. That's the reality!
Anyone who DOES have that wonderful life after starting to have kids in their late teens, is the exception to the rule! And few and far between. Although there does seem to be an exceptional amount of posters on this thread who started having kids at 18-19 y.o. who have several university degrees, a huge house, an illustrious career, and a massive salary. Funny that. 
In addition, re, this comment
reboot Id rather travel the world at 40 than 20
I had kids in my early 30's and travelled the world in my 20s, 30's, AND in my 40s. You won't be doing any travelling abroad for a LONG time, if you have kids in your teens. Why the hell would you want to wait til your 40's to go travelling? And don't kid yourself that you will be able to afford it by 40. You will probably still have kids at home then, and elderly parents to look after. So good luck with THAT plan.
And boo hoo to those who think people are being judgemental. People are just giving their views and opinions. Quit being so precious and hysterical. How DO people survive in the real world FFS?