You need to remember you can't weight train today for tomorrow and expect it to be all you need,...this is a lifestyle. Weight training today in your 20's....means you're also weight training in your 40's and 50's. It is not like you can put a reserve on your
muscle tissue to take out only when needed as you age. Use it or lose it.
Also, no one's mentioned diet. When women complain about bigger legs, in more cases than not, I've noticed it's because when they have very little muscle and more bodyfat, it's easier to squish those thighs into their jeans. Firm them up, and that tissue becomes less pliable and mobile, and they seem larger. If the measurements are larger, it's possible you're taking a small amount of muscle and increasing it,....but you are not dieting down sufficiently to ALSO reduce your
body fat and what's happening is a type of displacement. Sure, muscle is growing,...and it's sort of pushing the fat up and out as well.
So rather than worry about the new wonderful muscle you're building, why not think about leaning out to show it off?
Your goals need to be your own, we can't "tell" you....but those are some possible situations to consider.