My son age 15 just announced he is Bi, was my reaction ok??

I think your reaction was great I'm still not out to my mum, but when it comes, I hope she will react in a similar way like you did (but as I know her she will probably cry )

 

Haha my son did that news bomb thing, too! Ours was in the car about to drop him off for a music lesson - "So, I want to tell you, I'm gay. Thanks for the ride!" Ok, maybe there were a few minutes between the "bomb" and his exiting the car. I think I also said "Really?" before I caught myself and said "Ok, that's fine." It was all good. But totally dropped it on me, the clueless mother. Did the same to his brother and sisters - where's the milk, oh I am gay, can you hand me a bowl?"! We should be glad they could tell us. Period. And our unconditional love is all that matters.