I thought that was fairly intentionally left out because supposedly in her first life she isn't aware she's a mutant. She lives her whole life as an ordinary human not overly concerned with the affairs of mutants because she isn't one of them and passes up getting involved with Xavier because she falls in love with someone else and raises a family.
It isn't until she 'wakes up' in her mother's womb and realizes wtf is going on that suddenly she's interested in mutants and what their problems are and how to help and how to solve her own issues, among other things. It's only in life two she gets involved because it's only relevant starting in life two. Makes sense to me.