What should I change if I learned Brazilian Portuguese?
Switch your listening input to European Portuguese immediately, because ear training is the slowest thing to fix and listening is 30% of the grade. Then move your reading material across and relearn the everyday vocabulary that differs. Practise only on European-Portuguese exam material.
Start with listening, today
This is the priority and the order matters. Ear training runs on exposure over weeks and months, so it has the longest lead time of anything on your list. Every week you delay is a week you cannot compress later.
European Portuguese reduces unstressed vowels heavily. Words compress, the rhythm is faster and more clipped, and familiar phrases can go past unrecognised. The fix is not clever: European Portuguese radio, television and podcasts, on daily, at real speed. You are not studying it. You are retraining your ear.
Then move your reading input across
Portuguese news sites, Portuguese signage, Portuguese product labels. Vocabulary largely corrects itself once your input is consistent, which is far more efficient than memorising a list of differences.
The divergence concentrates in everyday nouns: transport, household items, food, daily routine. That is precisely the material the exam is built from, which is why this matters more for the CIPLE than it would for an academic exam.
Watch the writing paper
Spelling and register are where Brazilian habits cost marks directly. Forms of address differ in practice, and the writing tasks put you in exactly the situations where that shows. Getting the register wrong is noticed.
Do not practise on the wrong material
This is the self-inflicted version of the problem. Preparing on Brazilian-Portuguese material and then sitting a European-Portuguese exam trains the wrong targets and gives you false confidence about your readiness.
Every item in our bank is validated to European Portuguese and to the CIPLE format before it reaches a learner, specifically so this cannot happen by accident.
Keep it in proportion
You are not starting over. You have the grammar, the verb system and most of the vocabulary. This is an adjustment of input and a small set of swaps, run over a few months. It is not a second language.