Because the name puts it automatically as an adult site that doesn't help. Any adult natured site automatically loses value (unless you own porn.com or sex.com) and begins to gain value based on the traffic and in some rare cases the content.
So really what you have to do now is build the site up and get it a steady flow of decent traffic.
Because it is adult, it would be bases soely on your traffic. Although many things go into the value of a site, a general rule of thumb is, what it makes you right now per year * 5.