I know it's a normal weight for your height. I was just figuring that if you had lost that much weight that you thought you were overweight when you weighted 185.
Do you have any idea how to go about actually being able to show off arm definition for a woman? I've been lifting dumbells for a few weeks, and while I can feel a distinct difference when I flex my arms and squeeze, they don't look any different because I still have some fat on my upper arms. My forearms look pretty impressive when I flex, but it'd be nice for my upper arms to look buff too. =x
Arm definition is almost solely depend on the fat to muscle ratio and how you've built the muscle. How are you lifting the dumbbells? Hammer curls, bicep curls, etc? Just doing bicep curls won't really cause muscle definition, as almost all muscle definition (which is really the only thing I've been aiming for since I started working out 3 years ago) is from working out muscle groups rather than individual muscles.
If toning and shaping is what you're going for (as women almost always are; there are really few women that want to be beastly ripped), working out your shoulders and back are going to help as well as working out your arms (triceps, biceps, brachial). Pushups and pull-ups are pretty much the easiest and best way to tone and shape those muscles as well as using your upper arms.
Also, cardio. I know it's like the worst thing in the world, but if you're trying to burn fat, just do a ton of cardio. Ride a bike or run or swim a lot.
But yeah, that's pretty much all I worked on for the past year, getting my upper body trim. I only work out an hour a day every day and haven't changed my eating habits and I've gotten to where I am. The first time I flexed and someone was like, "holy sh*t, I can see every vein in your arms!" was a pretty awesome moment. I'm not quite where my boss at work is, where his veins and arteries stand out on his arms all the time (he's basically a gymnast, he does cross-fit, look up the workouts on youtube), but I'm proud of myself.