Hi Tim and welcome to the TFF beginners section!
I agree with the others above that just about every aspect of the particular kit tank setup you are discussing can be found to have serious faults when examined by an experienced aquarist, except perhaps the cute shape and the fact that it can be brought home in one box!
If you were a typical complete beginner bouncing around with hardly any information to go on except maybe a random fish store employee, then a little tank kit like that might be ok... but as of now, you're not! You have stumbled, in my opinion, on perhaps the nicest, most friendly and amazing forum around. There are an amazing number of very experienced fishkeepers and specialists here but there is also a spirit of sharing somehow maintained most of the time. I myself am a "re-beginner" from the old days and have learned more than I ever imagined.
The tropical fish keeping hobby is one of the very best things you could hope to share with a son or daughter. Often it ends up being a lot of fun for the whole family. Its one of the few things these days that goes against the trend of faster, more, louder and all the normal daily stresses of school and work. And the process of -learning- the hobby can also be the beginning of the more calm, patient feel that the end product hobby itself has if you let it be. Anyway, that's my plug for you giving a shot at the patience it will take to gradually pull the good info out of the members here and gradually learn the hobby with your daughter.
Once you have an info source like this its easier to abandon the kit setups and work your way through the basic decisions of the individual equipment needed. One of the very first lessons is that contrary to what one might first think, more water volume is easier for beginners. This is because water chemistry changes take longer to happen in larger amounts of water. You have more time to see something bad happening. Also, more volume means more choices of fish and greater numbers of fish. Most beginners think their desires for numbers and species will be modest but its the case that things are more limited than one first realizes and each bit of added volume greatly increases the choices and flexibility.
Another very early consideration is whether to site the tank in the child's bedroom or elsewhere in the house. Often noise is not considered until too late. It can require somewhat more expensive equipment to maintain the more quiet bedroom a child might be used to sleeping in. On the other hand, a tank in one's own room is a great plus in many ways for a child. A tank needs to be away from direct sunlight. It needs to be protected from high traffic areas, like hallways, where it might be hit or knocked. It needs to be in a reasonable situation with respect to warmth or cold so that maintaining the correct tropical temperature won't be too difficult.
Since you've already been looking at the water volume of 60L/16G you are way ahead of the game: 57L/15G to 76L/20G is great in that it is larger than many, many of the small tanks we see beginners struggle with. But its also good in that it doesn't get so huge that extra help is needed in moving the raw tank itself and it won't be so hard to reach in to or to drain and fill. All these are things to think about. Plain rectangular tanks chosen at a standard size have many advantages, not least of which is a wider range of accessories that fit and work well with them. Height is also a consideration: some tall fish like angels need at least 17" height but in general tanks that are not as high as that are easier to maintain and have better surface area for their size. Surface area is the prime determinant of gas exhange (water movement at the surface is also quite important.) Fish need oxygen and plants need CO2 not to be driven off to much, so its a balance. The type of light and wattage becomes important for success with live plants so that's another little decision that gets in your way initially.
I'll leave you with all this to read and discuss and I'll also give you your first homework assignment if you want: read three articles in our Beginners Resource Center: the Nitrogen Cycle, the Fishless Cycle and the Fish-In Cycling situation. Don't worry if they don't all make sense yet, there will be plenty of time to work on them. I believe there might be a good Tank Startup article there too by Miss Wiggle but I can't remember the title.
Good luck and again, welcome to TFF,
~~waterdrop~~
