It's possible.  I'd change it.

in an email.  What's the difference if your real name is in the address or the body of an email?  (And if they were really serious, LE could track down your name by other means.)Don't sweat it; do your research and only send emails to well reviewed, experienced providers, and you will have very low risk of having your name exposed.

Yeah, dude.  You can change the name in your e-mail From field and you should do it.  Only give your full name to providers who you are actually going to see (about to finalize an appointment).

As a newbie, you will undoubtedly not have a 100% e-mail to appointment conversion rate and therefore your real name will be in more places than it should be.  Minimize your exposure.  

Play safe!

Yes, you'll very likely need to provide it each time you want to be screened (especially as a newbie), but that doesn't mean it needs to be all over *every* email you send.

However, please don't change the "from" name to something sex-related (Haywood Jablome, Harry Pecker, Iluv Daty, etc.) or a female name. The first is corny (in the bad way) can send up red flags. I have a very difficult time replying to emails that have a female "from name", because I have had clients accidentally email me from, er, someone else's account before. Also avoid very very common names like "John Smith" unless you want your email lost in her inbox.

Your handle (provided J. Black isn't your real name) IS a good option. Or a combination of your handle and your city/state (Jeremy Mooselookmeguntic, for exampe).

But if you're from Bald Knob or Beaver Lick, please refer to the previous paragraph.

I have my real FIRST NAME ONLY on my hobby e-mail, not the e-account.  I registered the account with first name & only a Last initial.  I have given my full name for screening but do not need it on every communication that goes out.  LE really will not need to trace you through e-mail...  they can get ISP for a criminal investigation with the correct subpoena.  
Hobby e-mail is more of a protection from friends & family who might see your normal email over your shoulder sometime.    NEVER access your hobby account when there are others in your area.  I'd edit this account if you can, if not delete it & start a new one.
skb

LE can do whatever they want, whether you do it right or wrong.

Even a "free" account, anyone with a little knowledge can back track the IP address you sent the email from & get your location.

This entire industry is a huge risk.. but it's that what makes it interesting?