V4mpre

Hello, I'm thankful to be here (my first post), I apologize if this is the wrong section for this.

I am trying to remove both stock fenders from my 1990 coupe non turbo. I'm attempting to install aftermarket fiberglass fenders. When I go to take off the top bolts of the stock fender on either side the bolt wont budge and it rounds it off making it impossible to take off. I'm assuming its so old it just wont budge. How do I remove these ancient bolts even if they are stripped? not one came off or budged just stripped and rounded the bolt.

Thank you for your help, as I'm sure I'll have a lot of questions and I love learning about this car.