Start on the treadmill walking, lift the easy to learn machines, and stick to a routine. Diet is a great first start. Follow up with exercise. It'll help you keep the weight off and extend your life.
Keep at it.
As for what to do there, either book a couple of lessons or pick up a beginner weight program like Starting Strength or Stronglifts.
The thing is, getting used to the gym is often an amazing self esteem boost for people if you can just get over that initial hesitation.
Good luck either way.
I can empathise with this, I was 107kg just over two years ago and am now down around 85kg. Walking with a small amount of jogging (to increase heart rate slightly) was hugely instrumental but so was building muscle mass. Well done for getting started.
Something that worked for me (and may not work for you as a college student) was to start seeing a personal trainer with a focus on learning techniques to build muscle mass. I now am able to go to the gym on my own and train without my trainer, use a Smith machine and various other pieces of equipment and the benefits have been huge.
You don't need to go to the gym to work out. Walking is great, you can do a lot with a very small weight set, and you can do calisthenics. None are hard to learn, there's a bunch of websites and such. If funds and space aren't too much of an issue: stationary bikes, rowing machines, weight sets, etc. can be found pretty easily and are nice. Look for second-hand if funds are an issue.
Gym people do tend to be pretty great by the way. Not universally of course, but I'm sure you'd be able to find some who would welcome you and you likely wouldn't have a bad experience. You also can just go and watch or ask and it'll be really easy to find some machines you can do. Really worst case you can look up how to use different machines or equipment.
Since you're in college, a lot of schools will have classes that will teach you to work out in any way that you find interesting too. They won't expect you to already know anything or be in shape, you'll fit in fine.
I recognise that medication isn't a miracle solution but in some cases like mine, I'm not truely consuming as much calories as I used to yet I'm still weight so much. I do know that stuff out their could help me such as 2,4 Dinitrophenol or ephedra but both are illegal due to the side effects and the narrow gap between an effective dosage and toxicity. While I can recognize that these substances are not healthy long term, and they need to be respected, I also have trouble respecting that classification when I know how serious the side effects of common medications can be or how they can be abused just as easily.
Ironically I have trouble believing anything like this could help me would come to market soon. BAM15 is similar to 2,4 dinitrophenol but has less toxicity and is much safer but is no where ready to coming to market. GPL-1 drugs do show promise, I recently had to start one due to type 2 diabetes and other than slightly curbing my appetite it dosnt seem to be the miracle injection that is being proclaimed as.
All things aside, id love to be proven wrong and find out their is medication that could help me curb my cravings and boost my sloth like metabolism, but I also am warry of snake oil.
When I was younger, in my freshman years of highschool I was fat but it wasn't this bad. I wish I knew someone would have been honest and told me that I wasn't so overweight, and this may just be my mental health or body image perception issue but all I ever remember was people telling me I was obease and hearing bad comments, not that it was easily fixable. Iv suffered from back pain all my life and been told it was growing pains or my weight, I dropped 25 pounds but my back still kills me just as bad and some days walking can be to much, and the pain almost puts me to tears or causes me to feel weak in the legs.
TLDR: long life story stuff, I'm going to be skeptical