You’ll be damned if she has better things going on in life than you do. So, you feel this sense of competition with your friend. If she has a good job, you’re going to work your ass off to get a better one. If she runs a 5K for charity you’ll start training for a 10K, and so on. Rather than supporting her endeavours and successes you want to one-up your friend.
You might be feeling this way because of your own insecurities. There’s nothing wrong with a bit of healthy competition i.e. you and your friend pushing one another to become better people. But don’t take it too far. One person’s perception of what success is can be hugely different to another’s. My best friend might be happy if the football team she’s coaching win a ton of games; while I would be happy if I get a certain number of likes on my blog. It doesn’t even match up, they’re completely different things. Just do you.