Im in the EXACT same situation. Omg all the years of waiting for the golden ticket and it's just next week!! Im so happy but so frightened at the same time.
Just remember you(&I) have pretty much been conditioned to believe that we can't breath without our parents being there and saying yes to every breath. They have mentally got into our brain and told us big fat porkies of how we will get into drugs and alcohol and die in an alley somewhere without them. But that IS NOT true AT ALL.
Who got you this far in life?
If you say your parents, then you are wrong. You worked hard to get into university and secure your place. You walk and talk all by yourself and believe it or not, but you have your own brain too. you just have to wipe your mind of all the garbage they have fed into your brain over all these years.
Take everyday at a time, small steps and you will see living life on your own is possible. New, but not impossible.
Doing things like getting a tattoo should come after months of adjusting to living to your new life, so don't try an rush into that just yet. You have to slowly move into full independence, you cant just run up a mountain right? Take your time and relax, you made it so far after all
As for feeling guilty, you have no need to. This is YOUR life and you CAN steer it whichever way you choose. You have control of it. Don't feel like a spectator in your own life or trapped by guilt. You just have to let that **** go and move on. It's the last little leg holding you back from enjoying your life away from cultural ********.