Trying for a 4th and im so nervous!

I have 3 girls all 4 years apart right now and i started to get baby fever and talking to my hubby about it to my surprise he actally wanted to lol but now that we are actually trying all my nerves are kicking in... is 4 to many? Am i to old? Im 32.. will my other kids feel sad? What if its a boy iv never dealt with a boy! Lol all the bleeding and birth lol im just a ball of nerves anyone else feel like this? Or on number 4 who can give me advice on what its like to have 4? Id appreciate any mama support thank you!