well, I have seen two ages for mackenzie phillips in regard to her encounter with mick jagger. her book says 18, but there are some stories (pre-book, I guess) that say 13. for some reason, I thought she said she was 15 on the howard stern show, but I could be remembering wrong.
however, one thing remains weirdly consistent. mick jagger said to mackenzie, "i've been waiting since you were ten years old for this."
personally, I think it's unlikely he waited eight years, but whatever. maybe he did.
I have a feeling that when it comes to mick jagger (and john phillips, for that matter) my father would have felt his daughters were permanently underage. haha
but then again, when I got locked out of my own room (it was empty, I guess the lock broke) he used a wrecking bar to get into it. this would be after I tried every other way to get into it. he didn't even ruin the door. he was 83 at the time. and in that case the only urgency was that when we finished the mystery of the locked door he could go back to watching television and I could get into my room.