[name_m]Hi[/name_m],
I really don’t like my name [name_f]Caroline[/name_f] and need a nickname before going to college. Don’t really feel connected to most nicknames that are closer to [name_f]Caroline[/name_f]. How weird is it to go by a nickname completely unrelated to full name for ex: [name_f]Maddie[/name_f] or [name_f]Abbie[/name_f] or [name_f]Izzie[/name_f]. I love [name_f]Maddie[/name_f] and [name_f]Abbie[/name_f] and [name_f]Izzie[/name_f] but I don;t know people’s reaction if/when they find out my real name is not related.
I think it’s not that big a deal, having a nickname unrelated to your name. At least as far as new college memories. It might be trickier to start going by a seemingly random nickname to people who already know you as [name_f]Caroline[/name_f] (family, friends). But it’s your name and your joy!
Perhaps going by your middle name (or a nickname for your middle name) would bridge the gap?
Here are some less common [name_f]Caroline[/name_f] nicknames, in case you’re interested, too! 
[name_f]Carly[/name_f]
[name_m]Ari[/name_m]
[name_f]Caro[/name_f]
[name_f]Callie[/name_f]
[name_f]Lina[/name_f] (LYE-nuh)
[name_f]Calla[/name_f]
[name_m]Rollie[/name_m]
[name_f]Ro[/name_f]
[name_f]Carol[/name_f]
[name_m]Ollie[/name_m]
I agree completely that having a nickname unrelated to your name isn’t too big a deal, especially when you’re going to a completely new place with new people. [name_f]Abbie[/name_f], [name_f]Maddie[/name_f], and [name_f]Izzie[/name_f] are lovely names, and if you chose to go by those exclusively in college then that’s great! [name_m]Just[/name_m] introduce yourself by saying, “Hi, my name is [name_f]Caroline[/name_f], but you can call me ____.” I know plenty of people that have done so and I’ve never questioned it.
Another option could be going by a nickname from your initials? Ex., CJ, CC (Cece), CK, or CL (Ciel)
[name_f]Do[/name_f] you need to say your real name first or can you just start with nickname?
You could just start with the nickname 
It’s completely up to you whether they know your full name or not 
do u think its possible to avoid people ever finding out your original name or would they have to know at some point?
I have a brother who goes by a nickname that has nothing to do with his first name - it’s short for his middle name.
Most of his friends don’t know his birth name because A) he never uses it and B) the school mostly just calls people what they say they want to be called. And when some of them did find out? Nothing changed at all. They didn’t suddenly start calling him that. They kept calling him by the nickname. They laughed a little because his birth name is pretty clearly a wrong fit for him, but nothing more than that.
So basically, people at college may find out at some point that your birth name is [name_f]Caroline[/name_f] (a new professor might take attendance and ask for the first/last names that are on your official records, for example), but if you introduce yourself socially as the new name and never use [name_f]Caroline[/name_f], then people finding out your birth name won’t change anything.
Good luck. I hope your chosen name, whatever you end up going with, makes you happier.
I think [name_f]Caroline[/name_f] is lovely but maybe [name_f]Linny[/name_f] as a nickname?
I’d say these are more ‘preferred names’ than nicknames and that’s totally fine! I work at a school and many students use names unrelated to their ‘legal’ names
I guess I just feel I want a more substantial sounding nickname since I want to limit where I have ti use my full name
I think [name_f]Izzie[/name_f] works well as an unrelated nickname. I know someone who made [name_m]Izzy[/name_m] their chosen name, so maybe that’s why it works better to me. I also love [name_f]Coco[/name_f] as a nickname for [name_f]Caroline[/name_f] if you wanted something a bit more connected! [name_m]Kit[/name_m] would also keep the same beginning sound.
For some reason I feel like [name_f]Izzie[/name_f] works! I think it’s fine to choose a preferred name to go by, personally though I wouldn’t even introduce myself as [name_f]Caroline[/name_f]. just own whatever name you choose with confidence and people won’t think twice about what to call you. good luck in college! 
People won’t spend much time thinking about it. I really like [name_f]Izzie[/name_f]. What about rearranging your letters to [name_f]Linnea[/name_f]?