21, one child.. Am I trying too hard to get pregnant?

I had my first baby at 16. Healthy and so perfect. Now, I'm 21 and still with his dad and we're getting married! I had mirena for 4 years. It was okay but never had a period during that time. Last May, I had it taken out and didn't have a period until this June '16. Now, they're 7 days long and seem to be regular. I just don't know how to get pregnant. We have sex every other day during my fertile window. Is it too early for my body to understand how being pregnant works after not being allowed to for so many years?!