Why didn't she tell me about this?

maybe she didn't want to worry you.. or maybe it just hadn't came up... things like that happen maybe you should try talking to her and ask her why she didn't tell you.. but it really might be that she didn't want to worry about it.. do you worry a lot? that could be why not wanting to stress you out with worry.. I hope i helped a little bit! I'm sorry if it was no help at all