Thanks for the detailed write up. You do have a youthful voice, that's just fine :) Of course it'll come in handy with younger characters but still talking to other young people in spots like this. Watch the downward infection over and over. Hard to grow momentum. Nice fun in the FREE LUNCH section, really comes alive and you seem a lot more personable and interested from there to end. You don't need to switch with olive oil, that can be quite the difficult feeling. Rubbing a bit on the fronts of your teeth to limit lip/cheek stick, or experiment with chapstick or coconut oil, but don't obsess over this. It's a part of life and human anatomy, but with over articulating in the rehearsals and using a smile shaped mouth the noice will be lessened. As you self assess what ages "sound like" you'll likely find ways to give yourself more maturity without putting on a "voice" to do it. The confidence, delivery styles, how you think of the 5w's etc to ground yourself so that you believe you are the expert voice to help us understand the messaging. Nice work.