What's your kids age difference?

I'm in my mid 30's now and my husband and I are trying to conceive. Now I had my 1st child really  young so there really wasn't excitement. Now that I'm older, married, and actually trying my experience is so different. Now my daughter is 20 and I'm extremely terrified of having another baby. Everything is so different now. I'm so afraid and nervous. Her being so much older is a plus cause of course I have my "baby sitter" lol but again the gap is just so big that I'm afraid that I'm personally isn't going to have the patience or just going to worry to much. Also there is so many things that I would want to do that I didn't do with her that just makes me feel bad. Does ur kids have a big gap??? Has anyone else felt like that before with their 2nd, 3rd, etc???