How do i ask my Godmother if she would still like to host a bridal shower for me?

I wouldn't outright ask her. A lot of people who plan showers plan them as a surprise so she could be planning something and you might ruin what they want to surprise you with if you ask.

Also 6 months is still a lot of time before the wedding - a lot of showers don't happen until 3 months or less before the big day. I wouldn't ask her anything since its entirely up to her how and when it happens if she is planning one.

"Godmother, you offered to host a shower for me. Well, cousin has also offered. Would you want to co-host with her? If you would, I can give you her phone number if you don't have it."

So there are going to probably be people that tell you that you should not expect anything even after someone has already told you they are going to host a shower for you. As Munckin9218 pointed out it is a while before the wedding. When I was an MOH I hosted the couples shower like 3 months before the wedding. I don't know your Godmother's temperament but I know mine, she would be super crazy upset about someone else hosting me a shower but she wouldn't tell me. I know this will not be completely honest since it seems like your cousin is already planning a shower but maybe ask your Godmother if she would be alright with having your cousin host the shower? With the follow up of asking her if she would be interested in working with your cousin on hosting the shower?

I second this, there's no harm in asking. If she's planning a surprise, she may say thanks and let it go, and then coordinate with your cousin anyway.

Oh yes! this is a wonderful way to approach it~