Matching your hat to your shoe to your bag, or your necklace to your earrings, has a tendency to look dated. Mixing up your accessories adds interest to an outfit, and can make you look much more modern and polished.
The key to personal style is understanding your individual beauty enough to know which looks will work for you and which probably won't.
Your personal style should evolve with age. To say you want the same style at 25 as at 45 is a mistake.
I think that the way to have style is to accept where your body is right now, heavier or skinnier, whether you're going to change in the future and dress it as it is. The fact is you can always find clothes. It may be harder for plus sized people, I completely understand that. But I don't believe that it's impossible to dress with style.