I am not aware of a level 3 platinum.
The USAG developmental program uses numerical levels 1-10. Levels 1-5 are compulsory, where each gymnast does the same routine. If she is a level three, her biggest floor skill is a round off backhandspring, beam is a handstand, her whole bar routine is done on the low bar, and she vaults over a stack of mats.
The USAG Xcel program uses precious metals and gems across six levels, with bronze being the lowest level, sapphire the highest and platinum right in the middle. A platinum gymnast is doing saltos on floor, probably cartwheel or walkover skills on beam, jumping to the high bar and competing a kip, and vaulting over the table.
I do not know much about NAIGC, so if you are not in the USAG system, this won't apply.
There are YMCA nationals, Xcel nationals (I believe this is the first year it's not just an invitational) and developmental nationals. YMCA nationals has both developmental levels and Xcel levels. Xcel nationals naturally only has Xcel. And developmental nationals is exclusively for qualified level 10 athletes.
There are also NAIGC nationals, which again, I know almost nothing about.
Knowing what program your daughter is involved in will help get you better and more specific answers.