My mum and my sister were vegan, so when I was home for the summer holidays it made the transition easier. I would definitely say it's a slow process though! For example, not much changed in the way I ate, as I was already vegetarian, but if I went straight into being vegan, I would've found it a lot harder.
Definitely, switch things out slowly and you'll be fine. I've actually had a lot of fun learning to cool, and trying out new foods, I've definitely tried a lot more foods now than I would have before! Having fun with it and finding great recipes is key.
Please note: Do not use this personal story in place of proper medical advice - always consult a healthcare professional.