There is nothing wrong with you having the wedding at the appointed time, and there is nothing wrong with your mother attending it, if she avoids wearing adornment and perfume, because her going out in that case is going out for a need. But she must stay overnight in her own house.

If a woman is in ‘iddah following a revocable divorce, it is not permissible for her to go out except with her husband’s permission. But if she is in ‘iddah following an irrevocable divorce, then she may go out if she needs to, even if that is without permission, because she is no longer a wife.