i don't really think there is a set *age* that you hit and suddenly, wham, you're ready to have a child. i know people who had kids in their early 20s and they're great parents. i also know some 30 year olds i wouldn't trust with a Pet Rock, let alone an infant.
personally, i don't think i'm emotionally, physically or financially ready to have a child yet. and i'm 23. i want to be more mature, in better shape and have a lot more money before i make such a commitment, and hey... i've got time. :] my mother had me when she was 30, and i could see myself having a child around that age, too. maybe a bit earlier.
of course, i think teenage pregnancy is very problematic, and i think a lot of people rush into having kids because *omg they're cute* or because they didn't use protection. i don't think it's a decision that should be made lightly at all, but age isn't always the best indicator of "ready-ness". i know a couple (she's 26, he's 31) that have the most ridiculous, immature, close-minded ideas about parenting (you can't breastfeed your male child too often or he will become wimpy and too attached)... but they're about to have their first kid. are they the *right age*? most people would say yes. are they ready? oh, hell no.
as for people giving you shit about having children too early; well, fuck them. i don't even have kids, but i got married young, and people were all like "OMFG, SO EARLY, don't u want to enjoy teh single lyfez?!?!?!" yeah, no. people will judge and bitch no matter what you do... i suggest you just go on with your life, and if you're happy, then more power to you.
When I'm good, I'm very, very good, but when I'm bad, I'm better.