That’s a big range of draw force on that bow. Not that it matters much. If she is pulling 30 pounds, then yea, sounds like you have it about right.
If she is pulling a lot less than 30 pounds, then you might consider just getting the kids arrows from 3Rivers. They run pretty cheap and work pretty well. At least till you find out if archery is gonna stick.
If the bow is truly pulling 30 pounds at 18 inches, that means it’s pulling at least 50 pounds at 28 inches. Might be a bit much bow for an eleven year old.