If you are buying a new Nikon, they usually come with a kit zoom lens for not much more than the body. I think that may be a better more flexible way to go for you and your children until you guys figure out your photography and what is needing. 50mm is ok but depending on what you're photographing, you may not have enough room to step back far enough to frame your subject. On a APS-C sized sensor camera like the Nikon D5300/3300, it is the equivalent of 75mm.