Please note this is only the second critique I have posted, so if it's note entirely accurate, I'm very sorry!
Well, the first thing I'd like to say is the quality of the picture. I admire how you've coloured it, so that I like. But through a but of looking I noticed the 'quills' (or hair) behind her arm kind of pokes out unrealistikly compared to the bit on the other side. I think you could fix that by darkening it.
Also the pose is kind of distracting, considering she's kind of leaning on a weird angle, but it's really just a matter of perspective. Photos can be taken on an angle, this could be, too. So no worries.
Well, not to be rude, but it's not uncommon for sonic characters to just be standing around. I'm really unsure though if this is supposed to be a reference sheet, or something else. Reference sheets do generally have the character just standing.
But the thing I really like is your characters design. She has a great colour scheme, it kind of draws me to your pictures of her.
I really admire the teqnique you've used, like the way you shade and colour. I'm unsure about the line work, though. It's rather shaky. If you used a different kind of Pen tool or something, it would look even better.
Well, considering that the character is not really doing anything, it doesn't have much impact or inspiration flowing from it. No offence, it doesn't really have any meaning, but then again, it could be a reference sheet, and refs don't usually have any meaning.
You could draw Megan in different situations, maybe going to the beach or fighting, or hanging with a friend just go name a few.
Well, I hope my critique isn't too pushy for you. I would still like to see you continue with your wonderful style and improve overtime! ^^