Yes, it's a bad idea.
See, in all likelihood
it's just a crush. You've got a greatly... oh, I can't think of a more PC word... a greatly
overinflated respect for the woman, because she's the focus of your first exposure to a mind-blowing concept that might hugely change your life in various positive fashions.
IME, if you go out & meet a dozen more people with years of experience in stable polyamorous relationships, & evaluate them objectively, more than half will seem like better choices for you than your first crush.
People will say stuff like "oh, it's just NRE," but in this instance I'd say it's MUCH more problematic, & therefore advise that you MAKE NO LIFE-ALTERING DECISIONS WHATEVER while you're high on it.
You've probably spent most of your life being beaten about the head with halfwit Romantic notions of True Love or Destiny or Soul Mate or whatever. Meeting someone attractive, in the midst of a mind-altering paradigm shift, is highly risky. For starters, you are most probably
re-imprinting -- the article ain't much but it's indicative.
I'd be a little leery of your new friend as well. If she has ANY firsthand experience in "ethical nonmonogamy," she'd know (at least intuitively) that her behavior seems a little predatory. As trendy as it may be in SD, few of us have had moments where "I'm bi" happens to be admitted to another mom, who you've known only a few months, at the PTA meeting.
And if she DOESN'T have much first-hand experience, then she's overstepping, or at least overselling herself as a reliable guide. You NEED to step back, as does she, & address
wtf exactly is going on here.
Start with basics. Is your impression that she wants to have sex with you... or that she wants you & your husband to have sex with her & her husband... or you to have sex with her & her husband... or you & your husband to have sex with her? Is this a "let's hang out & see if we want to maybe get around to going out on dates at some point" thing or a "pack your bags, I'm bringing a U-Haul" thing?