Honestly she looks a little bit like Aria Blaze (Dazzlings, EQG) and the red pendant doesn't help. Frankly it's a little weird that Starlight and Aria seem awfully close in the colors department.
Well. If you cut out the age problem. Spike is potential male for everyone. He good with homework and brave to protect anyone. He save Crystal Heart before and recently just nearly became a dragon lord. He is a great supporter and is the male the have scene time that any male in MLP. XP
Uhhhh... I'm pretty sure that Starlight older that Twilight and FAR older that Spike. Considering that by Jim Miller dragons mature at slower pace that ponies... I doubt that this pair could work.