Don't give up. A 40+ (while it does show solid academic understanding) isn't the only factor when it comes to being a "good" tutor.
You can be the best academically but communication and an ability to teach your knowledge/the content in an engaging and effective way is just as important.
Personally speaking, I would want a tutor that knows their stuff BUT can also teach me in a way where i'm going to learn and retain the knowledge i'm being taught. Somebody who knows the ins and outs of the study design, past exams .. to know what to look out for and how to achieve the best possible result.
I am currently a teacher and when I see high achievers straight out from yr 12 that come in wanting to be teachers (on their placement rounds) - you HAVE to have that communication and engaging manner. I know it isn't the same as being a tutor but I thought i'd make that comment also. It's more than just marks/scores.
Something to think about.