Can you believe that I'm jealous of my son.
Oh no! Why are you jealous of your son?
Because he's so smart and he gets better grades than I did in school.
I'm sure you wish you were a better student, but it's wrong to be jealous of a family member. You should be happy that your son is doing well in school and getting good grades. Be proud of him and what he's able to accomplish, it wouldn't be possible without your parenting.
I just wish I was more successful.  I should have done better.
You're not alone in those feelings. A lot of people start wishing they had done more to be successful once they get older. It's never too late to find something you can work towards being successful at.