I'm 5 ft and 112lbs. Is 200cc breast implant too small?

I am sure you have tried sizers on your consultation and if it's a matter between 200 cc vs 225 cc you will not see significant difference as they are only within 10% of each other.  The implant will help shape the breast mound and give you a nice shape. When in doubt try the sizers again because most common reason for revision is for size.

25cc is about a sip of coca cola so I wouldnt worry about the difference, the smaller the implant is usually the better choice in my opinion because the implant is going to be pushing on the incision so the bigger the weight the bigger the force and the more your tissues will stretch

Choosing the size of your breast implants can be difficult. You should work closely with your board certified plastic surgeon about this. The correct size depends on a lot of things - even more than just want you want. It depends on skin quality, chest dimensions, body shape, etc.  For example, I often see my breast aug patients several times before surgery, just to select the best implant size. 200cc may be right for you, it depends.