I just read the first three chapters and this is a fantastic start to the story. Your writing style is great and I love the balance you strike between the characterization, the action, Theo's internal monologue, and a bit of world-building. 

Some thoughts from the first 3 chapters:

Theo's acceptance to the university is obviously deeply suspicious. The whole dorm is itself is sketchy; why is there anything his size when it should pretty much always be filled with Atlasians? Why was he accepted as a non-Atlasian male with his mediocre greades? Fishy.

 The various descriptions of just how out of scale most things are compared to Theo are very well done.

"It's ok, I won't break." Theo...who are you fooling here buddy? Definitely not yourself, and almost definitely not Gen.

"You're gonna have to get over that particular hangup pretty quick." Camille ain't wrong. So far, Theo's attempts at manliness have looked adorable as best and a bit sad and pathetic at worst. Also, Camille easily holding up hundreds of pounds like a tray...shit, just how strong are the Atlasians?

"I haven't seen anything to make me think otherwise at this point." Camille was preventing you from breathing when she held you, completely on accident and without knowing! I think that maybe, just maybe, they might be different from most other people in the galaxy.

The good news for Theo is all of the Atlasians have been very nice so far. Wonder just how long that's gonna last. Maybe until Roxanne shows up? The bit we know about her so far seems ominous. Regardless, excellent story so far.