Having prepared for it twice now (last year and this year), I can definitely say give yourself enough time. Last year, I must have started 2 months before the exam, which was in no way enough to exhaust all the possible exams and questions on the Medify package. This year though, being a uni student meant I had far more time, but still wanted to give myself enough time to prepare, so I started in January (so 8 months prep given that the exams were delayed this year). Trust me, there's far more resources out there then you may think:
- Medify question bank
- Medify exams
- Youtube videos
- Medentry (if you finish Medify and want to get it, but don't do so if it will burden your parents)
With percentiles, I'd say you need a 95+, given how competitive it has been in recent years, as students become more accustomed to the UCAT, scores will tend to rise subsequently. As an example, a score of 2920 would have been in the 95th percentile in 2019, but this year, was in the 88th percentile (so a 7 percentile drop). That alone shows how competitive it is. Don't underestimate how important it is, as it is the academic criteria which will land you interviews in most universities, before interview performance is used.