Is it normal to have second thoughts about your 2nd?

By so and I are planning to get pregnant with the next two months. We have an 19th old daughter right now so it would make her 2 and a half. I. Really want another baby I'm just not sure if I'm rushing it. Sometimes I get anxiety about if I'm making the right decision.  Our daughter was a surprise so making this life decision is freaking me out. It's a whole different feeling than being surprised. Is it normal to have anxiety about this?