You don't need to use a kit. Buying the ingredients alone will help you understand what you're putting into your brews better and will give you the opportunity to start developing your own recipes! Here's a simple IPA recipe I developed that would be good to start with:
8.5lbs Pale Liquid Malt Extract
1.5lbs Sugar
1lb Crystal 60L Steeping Grains
1.5oz Cascade Hop Pellets (60 minutes)
.5oz Cascade Hop Pellets (15 minutes)
.5oz Cascade Hop Pellets (5 minutes)
.5oz Cascade Hop Pellets (Flameout)
2oz Centennial Hop Pellets (Dry Hop 7 Days)
2oz Citra (Dry Hop 7 Days)
Nottingham Ale Yeast
3/4 cup priming sugar
There's nothing wrong with kits but by making your beers from ingredients that you select, you have greater control over the process and the end product. Just my $.02. I hope it comes out well either way.