That isn't chubby at all. I'm the same height and a little bit heavier than you and I can get into a size 8 in one shop and then a 14 in another. I don't go by sizes now, I go with what I feel comfortable in and if its a bigger size than what people people would deem as desirable thin or what I was a few years ago , I don't care. At those measurements, you are definitely not chubby, overweight, fat or anything like that. I am sure you have a figure a lot of people would envy.
Exercise might improve your health and your mood but you definitely don't need to do it to lose weight with your size.