I got my D3200 camera a few years ago and it was an incredible leap from the point and shoot cameras I had been using. With young kids, I wanted to be able to get some good photos and especially needed to be able to do so without flash. I have been using it with the stock zoom lens and have been happy with the results.
Getting this lens feels like the next big leap. The photo quality that I can achieve with this lens is astonishing, almost as much of a difference as going from point and shoot to the DSLR. I never felt like I could really achieve the number of pixels claimed on my camera until I took pictures with this lens. Now I can clearly see objects reflected in people's eyes when taken in good lighting. But the bigger difference is with poor lighting. Even in dimly lit indoor areas I can get bright and beautiful pictures with almost no noise.
If you are using the stock zoom lens, this will elevate your photos to a whole new level. Pick the focal distance that you use the most and buy the Sigma f/1.4 DG HSM Art Lens that matches, you'll never look back.