TSA and underage vaping?

I bought a Juul because I felt it would be least noticeable around TSA and the person I'm visiting. I plan to follow all rules reguarding e-cigarettes, but I'm just wondering if TSA will notice I'm underage, and what steps they would take after, if not just throwing away the Juul. Has any teen here brought vapes or cigarettes to an airline?

Can I view past flights even if I don't remember them?

I used to fly a lot when I was little but I don't remember the flight number and all that. Is there a way I can find out every flight I've been on by let's say for example, entering my first and last name, or my passport # at the time? Or anything like that? At the time my parents didn't have an account with the airline so I can't use that method.

Can I view all the flights I've been on?

I know there are sites where they show you but you have to manually enter them. The thing is, I don't remember the details because I was pretty young so my parents took care of all of that. At the time they didn't have an account on the website so that rules logging into the airlines website. I was wondering if like for example, Can I type in my first and last name and it shows me my list, or my passport number etc?

Buying a ticket for someone in another country?

I was going to book through expedia to purchase a ticket for my other half to visit his family in Sydney from Perth. But I'm not going to be with him.
I have read many things. I have a credit card which is prepaid and has $1300.00 on it that is available. I have his passport info but will I have to be present or can he just arrive at the airport and board the flight?

Identification On Airlines?

On December 26th I will be flying from Boston MA to California on Delta Airlines. I'm 18 years old. I will also be the oldest one traveling. (I'm going with my 17 year old cousin) I do not have a drivers license, but I do have a permit. Can I use my permit as an I.D? I amso have a birth certificate and a college I.D. What should I use for my I.D?