It was both - we see them both wearing their uniforms and kissing (that's the flashback) and then we see Andy's flashforward self going towards them, she reaches for the box with the engagement ring and Jack appears behind her in civilian wear (so obviously Jack in the flashforward) and says that they messed it up and then they kiss so, it was obvious, to me, that they ended up together and I'm glad about that. Yeah, the ending was a bit soppy, I hated the whole "station 19 is super special and we're all one big, happy family" stuff and, although the show annoyed me at times, I'm sad to see it go.