How stressful was your first year?

I’m starting at a different spot than most do so looking to hear different advice and opinions. I’m student teaching next school year, but I’ve taught preschool for years, was a para before that, and am now a building sub at a k-3 elementary school. I’m almost 30 too with 3 kids (6,5 and 7 Months). I worry it’s going to be too much when I get my own classroom. Tips?? I’m graduating with a prek-4 degree in PA.