I guarantee you are not the first person to do that!! I am sure there are many of us that did the same thing!!
Under your profile, you can select the Edit next to LNAB to change it. As on any other profile, you will get a new wikitree id using your maiden name. It wouldn't be a bad idea to send an email 1st to info @wikitree.com to make sure that won't cause a problem since you are an 'active member' so you don't lose your ability to login, etc.