It was, until Arie went Mesnick 2.0; now it's Becca's (if she wants it). Which is a good thing. I like neither Raven nor Raven 2.0: both are contrived Sassy Southern Girls.
Bekah is trolling. Gullible types are sharing the post with friends, with an "OMG SHE'S STILL INTO HIM" comment. It's by far her most commented-on post, so I guess it worked. She's this season's most-followed contestant, btw. (Speaking of gullible, she's a contrived Free Spirit. One big meh.) If she thinks she's going to be the Bachelorette, it's because she's too young to know the show's history.
Last, for everyone's reference, the age-appropriateness formula is 1/2 * man's age + 7. For Arie the minimum is 25, so Lauren B. qualifies. (The formula starts to break down after 40.)