She is 13, just finished Year 8. She's always been on the short side. She did have a bit of a growth spurt at the start of puberty but it wasn't as dramatic as she'd expected.
She is now about 4'11". Periods started about 6 months ago, she's convinced she's not going to grow much more. I've heard most growth occurs before periods start, but 13 seems very young to stop growing.