Hello!
I am a complete beginner in the art of bonsai and I'm completely unsure what to do next.
I've grown a sapling around 2 inches (see attached image) and I need some advice on my next step.
I've read that from this point there is a high chance it can grow too tall and too thin and flop over and die. Does it need repotting at this point and put outside or will it be okay in my window sill where it's been this far? I'm trying my best to keep it moist and not over watering it.
Any and all advice would be greatly appreciated!

Well, it seems it hasn't even "real"
needles yet!
IF I were you, I would leave it as it is for a couple more of weeks. When the real needles start to grow and the stem changes color to red, you MAY want to cut the tap root and repot. You don't NEED to do it.
If you put it outside now, directly under the full sun, it can die; change gradually from indoors to full sun.

UPDATE: I imagine it is a Japanese Black Pine, please correct me if I am wrong.

Thank you for your advice it is much appreciated, I will reassess over the next 2 weeks and hopefully it will grow some stability as the needles form. I'm not 100% on the type but it is slowly looking very likely to be a Japanese black pine.

If there's a good amount of sun in the window i would leave it there for a while till it gets a bit bigger like Clicio said. Not sure if that's a starter kit, but it can be hard to get the water to soak all the way through the soil they give you but it looks good to me.

Pines should be outside, and need full sun