I'm a female and I agree too. But maybe not a call girl, perhaps a sexual surrogate instead. A surrogate will work with you over sessions to get more comfortable with your sexuality and technique. Surrogates are trained and may or may not have sex with you depending on your progress. That means, by the end of the surrogacy you may feel totally confident to have sex with a "regular" woman and not need the penetration experience with the surrogate. Sure, a good understanding call girl may have experience acting as a surrogate, but that could be hit or miss.