You know you can Google that exact question and then do some research using IAFD, Indexxx, EBI and PTG. It's going to take some time but imagine the joy in finding some that we didn't name and more importantly. This is something you care about so why not dedicate your own time in making a list that you can then share with the rest of us.
Be advised that while you may find many names. It's quite possible that most of them got implants toward the end of their career or when it was already over so you won't see much porn with them already having implants.
Jessie Rogers and Riley Steele would meet your criteria. Ashly Anderson too. I think Peta Jensen was around 24 when she started and her enhanced titties are among the best around. Kimmy Granger was still 24 when she got hers. If you do do your own search, then I'd focus particularly between 2005-2013 as lots of stars got them done back then, some even getting boobjobs included in exclusive contracts! At this time, most stars who get them seem to be waiting until 25-30's to get them done.
^ Roll your eyes all you want. Suggesting people help others help themselves isn't a vice, particularly if the OP is already aware of names of people matching the description.
I know Chanel Preston was young when she started out. Hillary Scott and Brooke Banner also got implants. However without a repository of the dates of shooting with implants relative to their age, they may all have been older than 24 and thus I've wasted the OP's time suggesting those names.
I don't know their ages, but there's a scene with Loni Evans and Rikki Six in Cock Sucking Challenge 21 where they both seem pretty young and both have implants.