Hi! I am currently a freshman at UCSD. After a few days I realized it wasn’t the school for me and I applied to UCI as a junior transfer because I will have 90 units completed by the end of this year. My current UC GPA is 3.57. Is transferring from one UC to another really as hard as everyone says it is? I was admitted to UCI as a freshman and I’m afraid they’ll see that I didn’t choose them even though I now know I made a mistake. I know that I don’t want to stay at UCSD next year so if I don’t get accepted to UCI this year would it look bad to go back to a community college and then reapply again to UCI. I would just be scared to leave the UC system since I’m already in. Any advice would be greatly appreciated, thanks!
May I ask my UCSD isn’t the school for you? I am applying there as a transfer this fall.
One catch in your app will be that as a frosh they only have 1 quarter of grades to look at. But at this point, why speculate? You will know soon enough 
As for turning them down for frosh admission, they do not hold grudges.
If you go to a CC there may be a catch unless most or all of the units you used to get to junior status come from AP credit. If, instead, you were co-enrolled at a CC while in HS or took summer classes at a college of any type you may run into a unit cap limit, putting you into the category of high-unit junior or senior. See http://admission.universityofcalifornia.edu/counselors/files/uc-transfer-maximum-limitation-policy-chart.pdf
If you do end up going to a CC next year look and see if you are eligible for TAG which would guarantee your admission to UCI.
I actually don’t think it’s anything about UCSD specifically, I just quickly realized that going away for college isn’t what’s best for me. I think I chose UCSD only because all my friends were going away and I didn’t want to be left behind when all along I knew it would be best for me to stay local. It’s not that I’m having a bad time here, I just don’t feel as happy as I could be and don’t really like the vibe of the campus. For some reason I feel a lack of motivation since coming here and I really can’t pinpoint why. I definitely realize UCSD is an amazing school and I’m so thankful for this opportunity. It’s true that they have awesome professors, lots of clubs, an incredible library and gym, and the dining halls aren’t that bad. Overall, I think your decision should ultimately be based on what you know YOU want and what will make YOU the happiest because there is no doubt that you’ll be getting an outstanding education here if you decide to come! I think the main reason I want to leave is because I just have a better life back at home. Hope this helped!