Growing too fast!

I just watched my almost 6mo baby (September 8) go from crawling postition to sitting position in one motion. She's been crawling for a couple weeks, has been sitting unassisted since 4.5mo and has been eating solids since 4mo.  Am I alittle crazy that I'm shedding a tear?! My first baby didn't move this quick! I was hoping she would slowly grow. Instead she's flying along! 😭😭