Getting pregnant and having a child is rarely thought about in terms of optimal age, as there are so many other factors to consider. Relationship security, financial security, emotional maturity; these are the factors most people consider when deciding whether or not they will attempt procreation. However, from the biological research it seems that getting pregnant at or before the age of 30 is the best "bet" for your body. Women who have had one child before 30 had lower levels of breast cancer and less difficulty in getting pregnant overall compared to older women. However, this doesn't mean that once the big 3-0 passes, you're out of luck! It simply means that you *may* experience problems with your health compared to a younger woman.
Of course, if you're pregnant already, whatever age you're at is the best for having a baby! And while many people think you have to have "achieved" success in all the societal markers, that's simply not true. You will mature once you have a child, babies really don't cost that much if you don't buy everything in the store, and an apartment is fine. The most important factor to consider, over age, financial stability and the like, is the relationship you have with the other parent. You will need all the help you can get from the very beginning and while babies are wonderful, they can also be stressful. Wait if you can until you're in a relationship that is for life, because creating a life with someone means that you are linked, better or worse, with that person for the rest of your life.