I was considering skylake but when I heard they bend I said no no due to fact I have a spare noctua nh-d15.
The only cooler manufacturer to have any reported bending issues was Scythe. You'd be fine. Really. (Manufacturers such as Cryorig suggested that any possible damage would likely be during transport, but you should be careful when transporting PCs anyway. It shouldn't put you off Skylake; it's a great platform.)
What about Pentium G3258 now and put more money into gpu? Is there any difference between pentium and i3? I know i3 has 2 extra threads but would they be beneficial in games as there isnt any difference between i5 and i7
Even an overclocked G3258 will never be able to compete with an i3 at stock clocks simply because it's a Pentium. With an i5, you can be absolutely sure that there will be no bottleneck with any graphics card you look at - not in your price range, anyway. Although on a budget, you would honestly be better off with an i3. It's just the best value, and going from a 750 Ti or 950 to a 960 would make *so* much more of a difference than an i3 vs i5 would. Although you do want to be careful not to skimp too much on the CPU (i.e. with a Pentium), because it might become more of a bottleneck if you decide on a higher end (960+) graphics card. Generally, you want to look at spending about the same on a CPU as you do on a GPU with your budget - e.g. an i3 + 950 instead of G3258 + 960. Although ExRayTed's suggestion was good - but even a 950 would be able to handle most newer games in 1080p at 60fps on medium/high. And since your sister is only 9, she probably wouldn't notice the difference between that and a 960, with the kind of games she is looking to play. Ultimately, it comes down to how much money you're willing to spend, and what your priorities are.

I think those specs would be more than sufficient, though. Oh, and get a 2 x 4GB RAM kit instead of 1 x 8GB - it's the same price, but increases bandwidth in dual channel mode, a feature of even entry level (H81/H110) motherboards. Hope that helps.