What should I do before having a child?
Finish puberty first. Adulthood age is 22 or 25. All the way up to 32 or 43. If your a female or male. Then at 32 or 43 you're a fullly adult now.
Learn about what you're getting into. Taking care of a child takes a lot of work and money. Read some articles on the basic necessities of child care to see what you need to purchase and do daily. Some stuff is common sense, but there are definitely some things you wouldn't expect. We have a few articles that might help you out on child safety - www.superiorstock.net/childlockresources - but I highly recommend spending a couple hours researching about child care and necessities. Then make your final decision.
Be through school (or have strong local family support if you'll be having kids while in grad school and/or pursuing a professional degree), have a job with health insurance, be married, have several thousand dollars in savings. Stable job, stable finances, and stable long-term committed partner are more important than how much you make or where you live, and those things are highly dependent on cost of living in your area anyway.
Only you can decide
Have job stability. Have a source of income that is adequate for supporting you AND the child (diapers, clothing as they grow, the inevitable toys and electronic devices, medical, dental, maybe eyeglasses, enrollment in life-enriching activities such as sports or the arts, DAYCARE COSTS, and as they get older, either helping them get through university OR helping them with a down-payment on a condo. And, start to be able to add and subtract, you want to give them a monthly allowance AND some costs THEY need to budget for .. so they can learn how to plan and handle their money. I cannot tell you how much it will take ... here in Canada, I earned $60,000 a year (retired in 2014), but it was barely enough to support myself and my child and keep a car on the road, pay rent, etc. And I've never been very materialistic nor needed a lot of spending money. Where you live ... well don't live in the ghetto if you can help it. Try to find a neighbourhood that is relatively safe.