Rob Kardashian & Blac Chyna Feeling the Magic ... Long Before Hookup

1/27/2016 8:02 AM PST BY TMZ STAFF

0127-rob-chyna-splash-02Rob Kardashian and Blac Chyna's budding relationship might have its roots in a theme park trip way back in 2013. 

Rob and BC were photographed chilling at Six Flags Magic Mountain for Kendall Jenner's 18th birthday. The rest of the Kardashian family and a bunch of friends were there too. For the record, Blac Chyna and Tyga were still together

We know the Kardashian-Jenner sisters aren't happy about the new romance -- but looks like they at least gave the couple the initial stage to get acquainted.