Well, I'm a trombone player...married to a horn player though.
It is a very challenging instrument to play, in many ways the most difficult of the brass instruments. The main issue with the horn is that the bulk of the range lies in the upper overtones, so, one needs excellent embouchure control to move through the ranges.
Also, the mouthpiece is very tiny (like a trumpet), and sits on the lips in not the most comfortable way. Unlike the trombone, baritone, and euphonium which have a very comfortable size to fit neatly within the muscles surrounding the lips.
I can hardly get a sound out of a horn! But don't let me discourage your dream!
If you want to play some brass, perhaps you might like to consider the baritone. It is a lovely instrument, no slide (even though slides rule, they take some time to learn to use), and I think the most immediately gratifying to be able to produce a decent tone and some range. I understand the illure of the horn especially in the context of classical music, is potent. What a mighty instrument in the orchestral repertoire. But, trombones and trumpets have a much broader scope of music to play - jazz, rock, early music etc.
They are also cheaper!
Let me know if you have any other questions, or need furter explanations.
Scott