ONE child is a big place to 'start' I know from when I gave birth!!
An NQT is QUALIFIED, and has had experience. If she's out of her depth then so has every teacher who's got a new post ever.
My friend was 45 and an NQT, she had a major confidence crisis in her NQT year, she did brilliantly, but she felt out of her depth, scared, overwhelmed... through the support of the other staff, and their reassurance that she was there on her merit, she blossomed quickly... outwardly more quickly than her inner confidence.
I used to organised conferences for Headteachers, they sometimes felt out of the depth and overwhelmed too... I'm sure there are many managers on here who feel the same at times.
See past her age, and her prettiness, make friends with your age, realise you sound like a bitter old fart, you know, the sort of people you hated when you were young and able, and you'll be fine!