Given his age it's also not out of the question that [URL="https://pubmed.ncbi.nlm.nih.gov/24239151/"]alcohol intake could contribute.[/URL If] you drink weekly (for example, at frat parties) it will almost certainly have an effect on your lipids.
OP is also parroting the non-sense keto cultists always do. "Cholesterol is a lie, it's particle size that counts!" Which, in a strictly biological sense is true of course. However, for the vast majority of people (as in almost everyone including OP) elevated lipids are not due to a particle size difference but rather because of a fucked up diet, alcohol intake, genetics, etc. Here is a related study:
https://pubmed.ncbi.nlm.nih.gov/28460374/. However, even this study concludes:
Cholesterol is not bad. What people mean by it is you shouldn't go out of your way to avoid it. However, overconsumption can have deleterious effects if you're in an at-risk population. You may not even know you are until you get popped on a blood test. Certainly, eating 3 eggs in the morning won't do damage to most people. However, following "modern" keto and composing your diet entirely of cheeseburgers (no bread), eggs, and sticks of butter is not the same thing. It may be worth experimenting with a normal diet as described in the SS book.