A few things to consider when buying into a system like this for the kids:
1) Do you have enough space for them to build big things? We do but barely. So we have to limit some the size of projects.
2) Your kid's age is not as relevant as their ability to think practically and creatively as well as dexterity.
3) You need a steadyish supply of cardboard. This is not a huge issue most people on Amazon but something to consider.
4) The fasteners are definitely a choke hazard for babies/toddlers.
That being said, I think this toolkit is fantastic and really inspires our kids to think outside the box (LOL!). You will want to get in there too to help them bring their ideas to life because they are fun to use even for adults! This kit comes with everything you need to build some sizeable projects.