In my current/last session I have 8888/12566 xp at level 8 with only 2 stamina slots with almost any event finished, only missing some sex-related ones.
I also made the bad decision in this session to pick too many perks to maintain the 4.0 GPA for naught instead of patiently wait for the stamina upgrades to pick. This way it will surely take much longer to reach level 10 and further as long as I won't spend my aps to gain additional skill points.
The sum of days required going from 1 to 30 would be like 4.4 mio game days, so maybe a descendant of a player here will reach that in the next century.
I mean, it's okay if designed not to grab all perks and abilities in one playthrough until end of chapter 5 but there still should be a change about the achievements starting with 15 as these high levels aren't reasonably reachable.