Maybe it was just because I grew up in a big city environment, but Kenzie's behavior seems completely normal to me, even mild for a popular kid that isn't sheltered. I was a total goody goody (but not a snitch), so I got to see the hyper-sexualization and drug use with friends/acquaintances starting at 12-13, escalating as the teen years progressed. Based on college, kids exposed to this young, with a lot of independence, are the ones that don't end up date raped at the Frat, arrested for drugs or in the hospital getting their stomach pumped.
Annie has no street smarts (or book smarts), no "real" independence, no "real" friends, no moral guidance, no "real" confidence and emotional issues She already has a credit card and an apartment to start making huge mistakes with, once cars are involved, all bets are off.
MOD, PLEASE DELETE IF NOT APPROPRIATE: The biggest additional risk of LA, is "the industry". There are so many "open secrets" about manipulation and abuse, even with young kids. Thankfully, a man long rumored to have been a huge menace to young girls at "a children's network" was removed from his position of power just prior to Annie getting hired by "a children's network". It has been rumored that he could be responsible for one of his 16 yr old star's pregnancy, another's total continued public mental breakdown, and rumored abuse of MANY more that still grace our screens.
Hollywood is filled with people emboldened with enormous power taking advantage of those desperate to find, or maintain, fame and fortune. In the case of kids earning for their family, things get even more dicey. Maybe Katie knows what she is doing following Annie like a puppy and filming it all. Unfortunately, I don't think Annie would know what to do if she found herself "in a situation" and would be easy prey. Hell, the guy who created SevenAwesomeKids was arrested for allegedly molesting one of the girls on his channels; allegedly threatening her with contract fines if she refused to undress in front of him. Even third rate YT gigs aren't safe!
(I can link to an article with allegations from the warrant, but I don't know if that is allowed)