Later Life and Experience Points

Hello, I'm relatively new to Ars Magica and I was having my crew make companion characters for PCs. I have an experience point question: How many experience point a 23 year old would have? At what age do they start getting 15 experience points per year? I've look all over the book and the forum, but I can't seem to find a clear answer.

They get 45 XP for age 1-5, 15XP 5 to Apprenticeship (book suggests 5 years) (20XP per year if Wealthy, 10XP per year if Poor.) If not a magus it would be 23-5 = 18 years x 15XP = 270XP on top of the 45. Reference core rule book page 31 starting early childhood.

4 of my classes havent sent in the points yet. How do you know if they got it or not?