We cannot predict the score of an adaptative test such as GMAT by raw scores
2 extrem cases
> 47+ : U have the 3 first questions right and then u have for every 3 answers, 1 answer is wrong. All the rest are correct answers. In this case, u will have 2 correct answers with 1 wrong and with a start that is pretty high (the 3 first questions are correct)
> 40- : U have the last 12 wrong in raw.
In addition, remember that u have 25% of experimental questions, which means 9 questions. Imagine now that 9 of your wrong answers are experimental or that 9 of your correct answers are experimental
That's why... one should never worry about his brut feeling of commited mistakes
... We cannot predict the impact of those mistakes
By the way, good luck !