It's a really good effort for your first building in SC4!
Regarding the scale - it is hard to tell with only cars and empty space immediately around the building, so I'll take your word for it. In addition to the advice on the forums of taking your RL measurements and then scaling vertically 133% (which is correct), I will also say for a building like this, make sure that each floor is no more than 4.6m high in GMAX after accounting for the 133% scale (that gives you a RL ceiling height of 10' + the joist space in between floors common to a lot of these older style buildings).
The glass has a really unusual tint (which I actually quite like). It might be worth breaking up the large darker areas on the ground plane to avoid the strong contrast between the yellow and deep-green/black hues on the face of the building.