Ask your mom or whoever takes you to piano lessons to schedule extra private piano lessons to observe more about scales, arpeggios, and all that. Make sure you practice a lot in by-ear tests, chord improvisation and cadences, and sight reading. Stay cool, literally. It's the hot season right now, and tensing up can include nervousness and heat. I just go with the flow in piano learning, and I've passed 3 piano exams! I skipped Grade 10 to Grade 9, because I was an advanced musical learner in EVYMS, a professional school to prepare to be a concert pianist, and I am! Right now, I am on Mock 6 Grade Exam in East Valley Yamaha Music School.
Practice by ear playing by sitting backwards on the piano seat, playing a random note, and trying to figure out which it is. Experiment with white AND black notes. Then, turn forwards to see if you're correct. Put circle stickers on the keys with the key note on them to learn from. Then, look up and play a chord. Try guessing what key the chord is in, and do this with as many keys as you can, major or minor, high or low. Experience with all 24 keys, if you can, as a challenge!
Do you ever have to do improvisation with chords? I have to do it in OPEN POSITION. Which is really hard. But I manage to get an OK grade every time. :)
Good luck on your Grade Exam!