Cute OC. Absolutely adorable! I love her design. The pink and black is just so lovely. >.< Reminds me of the cat outfit from Cardcaptor Sakura when she caught the LIGHTENING card~
I did want to make one point (sorry, the artist in me says "Say something constructive, dammit!")-- so here goes. I love that you included her expressions on the page, but you're not really drawing the expression. You're drawing indications of it-- sweat drops, exclamation points, etc. The mouths are also matching the expression... but nothing reaches the eyes. They're all the same eyes, you've just changed the framing.
When drawing the angry face, try scrunching the eyebrows all the way down against the lids and add some lines to indicate wrinkles--it gives the face more gravity.
For excitement, try making the eyeball a little smaller and arching the eyebrows really high while making the eyelids angle down like you would for the angry face-- this will give the "I'm super-ultra focused on this one thing right here...!" face. XD It's really fun to draw once you start.
When working on a sad face, and this is purely a moe-adorable-ism, try making the eyeball wavery instead of smooth and bring the brows down close to the eyelids again. This will emphasize cuteness and saddness (in a comic way, though) at the same time.
These are just my recommendations--I've observed expressions in different kinds of comic art for a long while, and even if you don't use these exact ways, thinking about ways you can convey the expressions all the way through the eyes is important. ^^ I hope that it's a little help~
she is a sorta aloof girl, she wants very much to make close friends but is rather awkward and self aware so she can be over crytical of herself. But is in general a very caring and kind person who has a big heart to share!!!