You'll have a great time. I just went on my first ever cruise in March on the Norweigian Epic. My husband and I loved it. You're doing a good thing by coming here to research - I learned a LOT about what to expect. My first piece of advice is this: keep in mind that everyone here has different "favorites" and "hates". Take anything negative you read about your ship with a grain of salt and tell yourself you're going to have a great time, and you will. Epic is arguably the most hated ship out there if you read reviews, but we LOVED it.
Get the reusable straws from Amazon if straws are important to you. If you drink a lot of water, take a Nalgene or something so you aren't having to buy bottles. I drink water literally all day and the water on the ship is fine. Use the beverage package to try new things. You can get continental breakfast delivered to your room for free but the other stuff has a room service fee. So, you can order coffee to enjoy on your balcony in the morning, etc. before heading out for breakfast. Make your Cagney's reservation now if you haven't yet. Try the wings at O'Sheehans/ The Local (whatever its called on your ship). Decide where you want to be for sail away and get your drink in hand, this was one of the most exciting parts for us, heading out of Port Canaveral with an Aperol Spritz on our balcony, embarking on our first cruise experience.