I don’t know… One the one hand, she’s created this misleading idea about all the guys she’s slept with but it’s just a few and she’s never had an orgasm before, so her first and so far only is with a girl but on the other hand, she can drive, so. 😛 But really, on the other hand, there is the trauma that might account for the first part, not that she’s a lesbian.
I don’t really suppose it matters either way. But I think that as a fictional character who is the first billed of this series, it is less likely that she is written to be a lesbian.