I (25 -NB) am jealous of my sister (14f) and brother (15 m) and I don't know how to overcome it.

For context, I really love my siblings and we've had such a beautiful relationship growing up. They have become everything I hope they would become as people and I want to see them thrive. Lately though, I've been feeling withdrawn from them because they are succeeding at everything I never succeeded at when I was younger because of no fault of my own. I just feel like a loser at 25 and knowing they'll definitely finish college and prosper long before I do. The most evil part of me even wants to see them fail at times. How do I overcome these thoughts?