I am certainly no expert, but a couple of your points raise flags for me.  In particular, the absence of some key information (website, phone number) that I tend to rely on is worrisome.  Even more so is the absence of reviews.  One of the themes on this newbie forum is the importance of seeing only well-reviewed providers, especially when starting out.  In addition, those reviews should come from seasoned hobbyists.  The main reason is to insure the provider is legit, and not a scam or something worse.  In addition, with reviews, you will be much better informed as to what the experience and the services will be like.  

Ultimately it is your call, but those are the rules I followed when starting, and they served me well.

Many providers only want phone call for the first contact, many want only email for the first.  Provider's preference, which may be why she only has one or the other on her ad.  If she only has an email address, it is quite possible, as you mentioned in your post, that she will only give out her phone number to clients for directions to her incall location.

Many providers do not have websites and rely only on their ads on different sites to gain their clients.  That could be a reason she has no reviews, although a review can be written using only an ad website, providing it has the TER-required information.  Another reason for no reviews is that she doesn't want them for personal reasons, mainly privacy.

I would suggest contacting some hobbyists in your area and see if anyone has seen her.  You could ask this on your regional board as well.  It seems you have been doing your research, that's good.  If's also good that you are asking for opinions.  The rule of thumb around here would tell you that without more info, move on.  

If a girl has no reviews anywhere, I don't see her unless I can get some info from hobbyists I trust.  I don't care how how she is.  Safer that way for me.  BTW, I prefer first contact from me to be by email.  If she has only a phone number, I usually forget about her.

Swim

As a newbie, you are better off going with a highly rated well reviewed lady. Get to know the "dance" with someone who knows how to dance. Once you have the basics down, then expand into interesting ladies where you may have to Take One For The Team and be the first to review her (good or bad).

Regarding phone: Some ladies don't like the guy to waste her phone time, so only gives it out at the last minute. One lady I know only calls you (and blocks the number). Or, she could be a flake. Once you know the dance, you can better judge by all the other little cues.

ladies with at least 5-6 reviews from experienced hobbyists with a good review history; not reviews from guys with only 1 or 2 reviews (could be a LE sting).