I love how dude's say that on here but that's just not how a lot of women work.
It's not usually as simple as "she's interested or she's not." Women are complex creatures and seem to often have conflicting feelings around this sort of thing. Part of them may want it, but they may also be feeling guilt, worrying about potential consequences to the relationship or just fear taking the plunge into a strange and unknown lifestyle.
At the same time, women are also not typically as sex-driven as men. Many nights I'll want sex but my wife is tired, not really horny and kind of reluctantly lets me feel her up while she watches the news - then at some point, she starts to get horny, we start having sex and next thing you know she's riding me to orgasm, wants me to pull her hair and pound her from behind, then after I cum, she needs me to go down on her because, after already having two orgasms, she "got horny again" from me cumming in her. Yet, if I had just been passive and left her alone to wait until she was "interested" it would be a month before we had sex and we'd both miss out on many great nights of satisfaction. I can also tell you, she's in a much better mood the day after a good fucking.
On the flip side, there have been zero times when my wife came looking for sex and I told her I was too tired.
I know my wife is very turned on by the fantasy but she has all kinds of hangups and fears about making it a reality that may be acting against her interest. She also just has less drive for sexual adventure but has thanked me for pushing her to be adventurous and keeping our sex lives exciting.
Given how far she went already, I think she maybe just wasn't ready to go all the way the first time. You should talk about it during sex, give her positive reinforcement, show her how much it turned you on. Then probably you just need to create the right situation where she can be more adventurous again. Vacations always seem to loosen the inhibitions.