personally id say that your better off aiming for a higher score, especially if your capable of achieving it.
I was aiming for a 42ish this year, but because it was my first yr 12 subject i didnt exactly know how i much i needed to study and effort was required. If you are scoring high scores in your outcomes etc it doesnt give you an excuse to slack off. lol i did this unit 3 and it backfired.... mid year: B+
seeing that it's your first 3/4 WORK REALLY HARD and you will be rewarded, i know it's quite cliched but it works, when i realised that i got a B+ for mid yr i was pretty devo. I studied consistently in unit 4 and i am hoping for an A+ this time around, only had trouble with a few questions.
good luck