I don't want to be upstaging her in any sense

And you won't, because real confidence actually comes with a lot of humility. With genuine confidence, you're not threatened by being able to acknowledge that you lean on others to help you or fill in your vulnerabilities. In turn, the people around you won't feel upstaged because you're showing them that they're still necessary, regardless of the rank and station on paper. Confidence, and not arrogance, is something the both of you need.

You're at that age where confidence will change a lot for you over the next few years. Enjoy the ride. Listen to the voice inside your head that is nudging you in the direction of believing in yourself and knowing your worth. It won't change overnight but you'll grow in leaps and bounds over the next few years!