NO your not.
I was 18 when I had my ds, the unknown if far scarier than the reality, trust me.
Baby can go straight to a cot if you want, and it saves money, or a basket/lie flat pram/crib its totally up to you. So long as feet are at the foot and covers are tucket tight it doesn't matter what size. Or use sleeping bags for peace of mind.
2nd hand buggy is fine, if your on public transport you want something easy to fold but must be lie flat for a newborn, the pushchair topic here has a lot of info and help if you post what you need from a pram and your budget you'll get lots of help finding one.
Clothes, supermarkets are the best place, sleepsuit/babygrows are the complete all in ones, cover arms legs and feet, vests are like tshirts which popper between the legs. Or if your on facebook find local selling pages you can get fantastic bundles of great condition newborn bits. Matalans good for cheap snowsuits/coats.
If you get your bounty packs you'll get a voucher for a free pack of size 1 huggies newborns, I found them pretty good, although asda/tesco and aldi newborns get great reviews, first size I'd say get the ones upto 9lb/11lb
You don't have to spend a lot, I'm expecting dc 3 and have done it all on a budget as I sold everything after my big two. Facebook and gumtree are excellent for baby items going cheap.
Trust me, any age, or number of children we all feel clueless, I'm 24 now, have a 5yo son and 3yo daughter, but feel totally lost at how to care for a newborn, but you just do, it comes naturally and you'll be just fine. Xx