Should I enroll my child in Pre-K?

I’m having trouble deciding whether I should enroll my four-year-old in Pre K mainly because I’m six months pregnant & will have another tiny one by the end of November. I don’t want to deal with all the sickness & illness that might come once my four-year-old starts school; what do you guys recommend? I can definitely wait till next year for kindergarten. My 4-year-old is very smart, so I feel she doesn’t need Pre K right now, but I also don’t want her to feel left out. Please help a momma out!!!