Girls are treated with equality. That was a fundamental difference between sikhism and any other religion. Children, men and women all have the same rights and can perform the same ceremonies and be on the committies ( they certainly are in England). However personal prejudices from individuals are more difficult to overcome and go beyond sikhism.
Sometimes you may find women don't want to take an active role because they have other commitments. Its not that they are not allowed.
As for women holding the kirpan, five k's applies to everyone ! therefore you are holding the kirpan. But in a wedding ceremony which a very important day in your life do you want to be the one holding the kirpan. This is more a question of respect, people would think your husband was dominated and give him little respect ! is it a big enough issue to cause that kind of disrespect for a loved one ?