Body after baby #3

I weigh about what I did before I had my last baby, as the last few pounds came off gradually over time. But my body is different! I don't fit into my old jeans as well .. and I am softer. I expected that somewhat but I figured being back to my happy weight would mean I would fit into things ok! I was tempted to just try and lose more simply with calorie counting and I would eventually weigh small enough. But I would have to eat barely anything to lose at the current weight I am ... so thats out! My question is ... is it ok for me to work on strength training & toning without being too strict with my calories? I don't want to lose weight, or much anyway, but I want to tone up! Would I really get results that way? In the past when I actually had weight to lose I just counted calories and exercised ... but this scenario is different as there is no weight to lose. Hope I am making sense! I weigh 125 lbs, am 5'5, and wear between a 7-9 jeans.