Hi, I really would like to start knitting but im completely clueless on what circular needles to buy. I crochet with aluminum hooks and I was looking into buying a metal interchangeable needle set, so that i’d have the needles i wanted on hand for other projects. I also looked into starter sets but i still wasn’t sure of what kind of needles to get. theres short and long needles and then there’s cord sizes. Please, help.
i want to knit hats and baby garments.

Welcome to KH!

If you aren’t sure what material needle you’d like then I suggest a sampler set which will have both types. KH sells Knitter’s Pride which is a really nice interchangeable set especially to start with. I actually use mine all the time and with some yarns I use wood and others I use metal. I bought this sampler set before I bought a full set.
There’s also this sampler, but I haven’t tried any of them or bought the set.

Here’s their website.

To knit hats in the round for babies I suggest you learn to magic loop. It requires interchangeable needles with a longer cable. For adult hats I use a 40", but for a tiny baby you maybe could use a 32". I prefer longer, but that’s personal choice. You’d have to buy the cable separately I think. I’m not sure what comes with a set and they are all different so check.