Depending on what the other red flags are, I’d say go out on another date or two and see what happens. You’re not getting married, after all. Also, thinking she might be “The One” after only one date is putting a lot of pressure on things. You might want to scale back your expectations and just try to relax and have fun.
The funniest person I have ever known was a Jehova’s Witness. Do NOT let that hold you back.
I think elmwood is putting the cart before the horse. One of the major purposes of dating is to find out if you are good for each other. Another is to have fun. It sounds like the latter is assured, and the former a distinct possibility. So date. It may not work out, because of the religious issues or because she decides your nose hairs are too long. Or it might work out just fine, and you discover that the religious issues are not that important, or one of you converts, or you both become Presbyterians. There is only one way to find out how you really feel and what really matters. So date.
p.s. A connection like that is a rare and beautiful thing. Don’t throw it away without giving it a chance.
Not everyone dates to have fun. Some people date to find The One.
I say “Go for it!” I think you’re wasting your time, but WTF does it matter what I think?
Lots of examples were given here about people of other faiths being really great, funny, whatever. But notice, there are not a lot of stories of people marrying someone of a very different faith (and staying married).
Besides there is something intuitively wrong with this picture. She lived a wild fun life…recently converted to the opposite. Hmmm, there’s something about her that you don’t yet know. Some history. Probably mentally unstable. Just a guess of course. But something isn’t right here. She’s on the rebound, or not JW at all, or something. Be careful out there - and wear a condom!
For me, JW = deal breaker. I consider JW to be something of a cult. YMMV, IMHO, etc. etc. etc.
FranticMad, with regard to
"Not everyone dates to have fun. Some people date to find The One. "
Doesn’t that go with "One of the major purposes of dating is to find out if you are good for each other. "? Personally, I don’t believe in “The One”, but I also don’t believe that there are very many really good matches. If the current divorce rate is any indication, many people end up with someone who is not a really good match, or else they don’t stay that way.
You’re right, maybe there is something wrong here. Or maybe JW thoughts just made sense to her. Or maybe the JWs are right and she discovered that. Or, maybe there is something in both of their natures that lend themselves to consider the JW way of life, only elmwood doesn’t know it. Or, must likely IMNSHO, maybe she wasn’t really happy leading that “wild, fun life”, and was seeking something more meaningful to her, and found JW, and elmwood is also seeking something (which seems to apply to a fair number of Universalists). Or maybe they find each other so hot, they can’t tell lust from love. I say there is only one way to find out. Date.
I’d say go out with her and see where it goes. If you dont like the expectations placed on you then break up. My cousin is going out with a JW and I suppose he is one too although he denies it. I have seen him maybe 3 times in 5 years only because I run into him at the bookstore and sometimes I have asked him how come he doesnt come around. He says he is at the church or doing church things or that his girlfriend doesnt like it and they dont hang out with non JW’s. All his former friends wonder where he has disappeared too. But then again I guess he is happy. It is his choice and so even though he says he has not converted he doesnt really associate with anyone from his pre JW days prior to meeting this girl. But if you really hit it off and it doesnt bother you and she is a new convert I dont think she will ask you to cut yourself off from others. Goodluck.
I’m a barely-practicing Unitarian Universalist, with what I describe as a “Christian Lite” mindset, who just recently started to return to church, after moving to a new city.
Mom’s Lutheran (LCMS). Dad’s Jewish (conservative). They’ve been happily married for 45 years. 
My SO is a practising Christian, whereas I’m atheist through-and-through. We went the route of laying down some ground rules, and as a result have never had any problems.
While I freely admit that I just don’t get the concept of religion in any shape or form, I respect his beliefs and understand that they mean a lot to him. Therefore, I don’t question or “trash” his faith. Likewise, he doesn’t question or attempt to convert me.
I guess you could say that we both regard religion, or lack thereof, as a very personal thing. We have plenty of other things in common besides, and those are what we base our relationship on.