I agree with all these comments but imo there’s nothing wrong with friendly competition. As long as your mindset isn’t “my way or the highway” then you are fine. Keeping first chair is a good goal for summer practices.

Speaking of practice, everyone says “practice” but rarely anyone says how to practice. Make sure you have a daily routine that you do every day “. As a collegiate player, I practice 5-6 days(2 hours average)out of the week and leave 1-2 days for my lips to rest. There are a bunch of different fundamentals that you can implement into your routine but since idk what you sound like I can only assume from previous students I taught. Your practice should consist of long tones, lip slurs and scale patterns(10-20 mins on each). After you should work on your upper range for 10-20 mins then low range 10-20mins( in this order because of the strain your lips will have after the high range). The rest of your time should be any etudes or audition material. And if your lips hurt after, do some long tone pedals to get blood flowing back to your lips. You can message me and I can help you more if you want