[TheLegacy]

The answer truly depends on how prepared you want to be to look silly and foolish in front of her. Do you know if she has taken any lessons? If she doesn't know how to ride, then there is something to be said about learning together and looking silly as a team rather than you appearing better than her.

It's great that your asking these questions and shows how much you care for her - but highly suggest that you have a change of clothing so that afterwards if your planning dinner you both don't smell like horse sweat.