I sent a friend a message telling him that I’m transitioning my gender, his response confused me

For context I’ve known this guy since out university days back in the mid 80s and we’ve kept in semi-regular contact ever since, so I sent him a message telling him that I was transitioning my gender to female, and got a reply back 20 days later with just this 😮 the Wow! Emoji

And he’s been online frequently during that period, honestly I don’t know how to take this?

Is he shocked?

Horrified?

Upset?

As an autistic I don’t really understand emojis