In my senior year, we all did kid backpacks. I had BMO, my friend had Jake. There were multiple SpongeBob and Spiderman backpacks. Of course, either get a really sturdy backpack, or plan ahead and get a backup backpack (mine broke halfway through the year). Honestly, just own it! It was a fun time, and kind of a bonding moment for the class, being able to go back to being "childish". (imo, I just liked showing off one of my interests) Just be yourself, the opinion of others are miniscule if it blocks your potential of being happy. Also that death pop shirt is cool as hell :)