We're seeing some good choices here... I wanted the Arbalest and Liger Zero. But never fear, I have moar mecha under my belt... assuming that they don't get taken anytime soon.
Can the mecha that we are choosing be like a giant thats like more bigger than other mechs?
Tsuyoshiro already chose EVA-00 and that thing's a giant. So yeah you can choose something like that but the main requirement is that it must be pilotable.
Well this is pilot by hundreds of people: Answerer from Armored core for answer
Spoiler:
The Answerer is pending for approval. It will be judged if it's a mech or not. You'll receive and an answer later today.
The Answerer is considered a mobile fortress and therefore it's does not meet the requirements to be a mech. However your White Glint choice is approved.