4th Class requires 36 months of qualifying service, 6 of which must be at sea as part of the Engine Room watch. The 6 months are covered by Memorial, and all other Colleges, as part of their approved Cadet programmes. During College time, Skills Training and Record Book for STCW Certification and PPS1, are also covered, that's why you get to challenge 4th Class exams.
You have 90 days from Convocation to challenge 1st Class theory exams, too. I suggest you take the opportunity, what do you have to lose? If you pass, it will save you several thousands of $$$ taking block credit courses later. If you fail, well, at least you tried, you've lost nothing.
The other, alternate path, needs 36 months too, 6 of which must be at sea. Skills Training was a 1 year course which includes the TC Record Book. This course is generally not offered, schools can make much more money from Cadet programmes. They offer Skills courses, covering Electricity, Machining and Welding (required in STCW) as block credits for several thousand $$$. Required MEDs are offered too, at several thousand $$$ each, so you can see why the one year course is not offered now, it covered all these topics and included PPS1. Much more profitable to split it up and charge by the topic instead of by the course.
Discourage incest, ban country "music".