e30st

Hi!
Sorry, the question might have been previously asked, but didn't find it.

I have an ESTA, with which I have travelled to the US many times. This Saturday I'll arrive to JFK T4 with my little sister. She is under 18, can't speak english that good, and it will be her first time ever in the US, also with an ESTA.

In JFK T4 (when I was there last time in December), there is a separate line for first time ESTA visitors and returning ESTA visitors, with them going to the same line as US citizens, while first time ESTAs are going to the line with other travelers, who travel with Visa.
In other airports (like ORD, LAX, BOS, SFO, EWR) there is no separate line for those who are entering first time with an ESTA.

My question is, can I bring my sister with myself to the returning ESTA line, or we shall go separately? Would there be an error message, if she just went straight to those kiosks? (in T4 for the first time ESTA visitors don't get to use the kiosks, just go straight to see an agent).

Thanks.