Hello, I'm new here. I hope I'm posting in the right part of the forum to ask this. I played flute for 27 years (great now that I've counted I feel old)

I went through school (marching & concert band). My senior year I got my first open hole flute. Love it. I also enjoy playing piccolo. I taught myself to play alto saxophone, guitar (thought not as proficiently as the flute). I was considering taking up the French Horn until I discovered the alto flute. I know it may seem impossible to believe that I've played this long & just today learned of the alto flute's existence, but I promise it's true. I don't play in concerts, just for my own enjoyment & also go play at nursing homes from time to time. Have occasionally played in church or events like that.
Is playing the alto flute very different from playing my current one? Is it a significant difference to transition from one to the other? I had no trouble going from flute to piccolo.
I'm sorry if this is a repeat but I didn't find my answer when doing a search. Thanks in advance for any info you can give.