Hello! I have two options for you:

Thomas Montgomery is in her year, but he's a Ravenclaw. He's on the Ravenclaw quidditch team. He's actually a really nice guy, but he has quite a temper and can come off as grumpy as heck depending on the situation. He won't mind that she likes quidditch! If she enjoys transfiguration, he'd also chat her up.

Clementine Rookwood (who is returning in July, so it'd have to be a future thread) is in the year above her and a Hufflepuff. She's really sweet and a 'mom friend.' I imagine she's probably been very friendly to Hermia, and maybe they've helped younger students together?