The YMCA at the Piscataway Community Center

One adult= $50/mo plus $60 sign up fee

You can join by visiting branch or online here - https://www.ymcaofmewsa.org/locations/the-ymca-at-the-piscataway-community-center

There is a monthly membership fee, which depends on family size and age, but includes the gym, basketball court, pool, and Raritan Rapids Spray Park. You can go in person to speak with a member services representative, take a tour and ask questions, or go online and register to become a member. There are staff members who speak Spanish.

Is there such programs that have girls only for swimming

Yes there chair's and tables all around the water park

Yes

Here is rate card - https://www.ymcaofmewsa.org/docs/default-source/default-document-library/ypcc-piscataway-resident-rates-page-1-only.pdf?sfvrsn=deda4747_4

Yes open to both resident and public.