Can kids use I485/AOS EAD after turning 21

[Ram P]

My EB2 PD is 10/25/2013 (Underlying 140 approved in 2013)
Filed AOS/485 in May 2022 when FAD was current and received AOS EAD for myself, spouse and 16 years old daughter. Currently all three of us are on H1/H4 and never used GC EAD.

Question: Can we use GC EAD now? Will it impact my daughter's stay in US or College when she turns 21, in case we don't get GC by then? 
Or Should we continue to stay on H1/H4 and switch my daughters to F1 before she turns 21.
What are the pro and cons of using 485/EAD, keeping my daughter's age, her upcoming college etc in perspective.

Please advice and share your experience

Thanks in advance

[newacct]

If someone on H4 works outside H4 EAD, they lose H4 status, but it does not affect anyone else's status. If someone on H1b works outside H1b, they lose H1b status, and their H4 dependents also lose H4 status. However, they can continue to stay in the US for as long as they have a pending I-485, regardless of whether they have status. They can continue to work on their I-485 EAD as long as their I-485 is pending.

Regarding your daughter's aging out, if her I-485 has been filed, then her CSPA age is frozen in the first month that a visa number is available on the Final Action Date chart. (For example, if I-485 was filed during a month when a visa number is available in the Final Action Date chart, her CSPA age is frozen. But if her I-485 is filed during a month when a visa number is only available on the Dates for Filing chart, during a month when I-485 was allowed to be filed according to the Dates for Filing chart, then her age is not frozen until a month when a visa number is available in the Final Action Date chart.) So from your description it seems that her CSPA age has already been frozen, and since she has not aged out, she will never age out on this petition, no matter how long I-485 takes.