Every skill is maxed at a skill level of 5, and each XP level you receive one skill point to allocate to a skill. However, to get a 5 in a skill requires a total of 15 skill points, which would require you to level 15 times for a skill you have at 0.

HP increases each time you level, and also by increasing certain skills. The specific skills are outlined in the Character Creation rules.

If my calculations are correct to get to level 250 it would take 88034 days with Pilot skill 6 and HS 15. That is if you went from corner to corner of the galaxy. :)