It's already real for you, but you can make it extra real when you're there. Regardless of your age, there isn't going to be a feeling that can compare to you waving your wand, saying a spell, and that spell actually working. There are interactive sites all over Diagon Alley where if you say the right spell, it'll happen. It'll be so amazing that you'll probably be even more upset when you go home and sit in the dark because no matter how many times you scream 'lumos', the lights never turn on. If you know of any other secrets that fellow Harry Potter fans will enjoy on their visit, write them in the thread below. Mischief managed.