Am I smart enough?

Long story short, I never finished high school and received a home school degree which if I am honest I should have never received because I never did the work. I spent 16 years raising kids while following my husband around in the Army. My kids are grown enough now and I am working but I want to get a degree so badly but I truly don't think I am smart enough. I was never good at school while I was in it and have just "faked it until I made it" most of my life. I am tired of feeling the way I do and keep telling myself to at least try but I can't find the courage. I am almost 40 years old and have done nothing besides being a wife and a mom. I want to have my own life and I think I just need encouragement or stories from people who were like me when starting. Thank you for listening to me babble!