Prepping for Oxford MAT - Disappointment

I am applying for Math & CS at Oxford.
I just completed the 2017 MAT paper for practice and ended up with a 78/100.
I am aware that this is from 5 years ago and so it is probably easier than what I will be getting...
Because of this, I feel really disappointed. Should I?

Keep at it! You’re probably doing fine at this stage plus the format will be all new with MCQ only so with the score from long answer included probably not representative there.

In particular, I scored 36/40 on multiple choice questions, and the extended questions were where I dropped tons of marks…

Keep at it! You’re probably doing fine at this stage plus the format will be all new with MCQ only so with the score from long answer included probably not representative there.

I don't think they're planning MCQ only; see:
https://www.maths.ox.ac.uk/study-here/undergraduate-study/maths-admissions-test
In 2024, the MAT consists of 27 questions. All candidates should attempt all questions. Of these, 25 are multiple-choice questions of a similar style to multiple-choice MAT questions from previous years. Each multiple-choice question is worth 2 or 3 or 4 marks, with the number of marks for each question given alongside each question.
There are two longer questions, for which candidates will type responses. Candidates are not expected to type complex mathematical expressions or use any symbols beyond those included on a standard keyboard (alphanumeric characters, + - =, and similar). As with long MAT questions from previous years, candidates should expect to justify their answers or explain their reasoning for these long questions. Each of the long questions is worth 15 marks. The responses for these questions are marked by a team based in Oxford, and partial solutions are awarded partial credit.