Some great advice appears here, as usual. Here's what I'd add.
Since you've already done some crossdress-ish things with your wife, chances for you and her getting through your bigger reveal are good; you have reason to be hopeful. If you're both open and honest with each other, you can find ways of accommodating to each other's wishes, and that will determine how far you can go in including her in your "en femme" activities.
Think about how much easier it will be for her to handle your saying, "I have to tell you about something that I did two weeks ago, and what I learned about myself," versus "I have to tell you about something that I did three years ago ..."
I think there will never be a better time for you to discuss this than now.
Best of luck to you both.
