Congrats on starting Aikido. I only discovered it myself in September and have remained fascinated with it ever since. In terms of what to come, I'd say you're in for a treat as you begin to learn more techniques, counters, breakfalls, etc. Especially the breakfalls. Stuff that looked like I'd never have the nerve to do are now fun and I'm always looking forward to taking a new type of fall.
You'll also discover much of the philosophy behind it and learn how all the pieces of the techniques go together and the techniques start to flow better. Once you've begun learning about your center things'll flow more smoothly.
In terms of testing you just need to relax (something I failed to do on my first grading). Rank isn't as important and the skills that are needed to acquire said rank so as long as your Aikido is good don't worry too much about rank and how fast you can make it to the next one. Enjoy the trip.
But the main thing you can do is to keep your love of Aikido with you and you'll be fine.
Just my two cents.