Don’t worry, everyone has to be new to something once to get good at it! You can tell the gender of some animals by their colors or other features not including genitalia so I can see where the confusion could have come from. Leopard geckos, however, you can only tell by looking at their genital area from underneath. If you post a picture like the examples someone else posted I’m sure someone will be able to help! Congratulations on your new gecko!