Yes female chameleons will lay eggs regardless of if they have been with a male. they can start laying as early as 6 months but it is usually from a year onwards so it is best to have a lying bucket in the cage from the 6 month mark. You can try and stop your females laying eggs by cutting down food and keeping her n the low 80's
As described above, you can limit food intake and keep temperatures low so that she either never lays eggs or she lays much smaller clutches (number of eggs per batch), both of which will help extend her life. Egg laying is tough business for them!