I'd recommend looking at mostly used boats that are in the 8'-9' range. This sport has a high turn over rate for new comers. Save yourself some money early on, when you have no idea what type of boat you'll like best. After you develop your skills, you'll have a much better idea on more specific types of boats you will prefer.
^^^
This, x-1,000,000. I've been into kayaking for 22 years and this advice has never changed. Your first boat should be purchased used, cheap, and as soon as possible. Budget $300. You can often find them with sprayskirts included.
This is not the time to look at new kayak websites or shop in stores. Hit Craigslist, FB marketplace, or the for-sale board at your local college. It's summer. Buy a boat and get on the water.
Find some nearby flat water and get your butt in your kayak and spend as many hours as possible simply farting around. Learn to edge the boat, feel paddle strokes.
Watch some videos on good forward brace and sweep stroke fundamentals.
Get to the local pool or find a friend to teach you to roll. The sooner you learn how to roll, the sooner you will push yourself to work on edging and boat control--because you know you can roll back up if you flip.
Find a solid crew and get on some friendly Class II/III whitewater and learn to read water. Dress to swim. Bring beer. Enjoy the river.
Next winter, shop for more specific boats.