Just find someone who knows what they are doing. If the sex of the snake matters to you for breeding purposes (which you've stated it doesn't), you won't want to screw everything up because you <i>may</i> have popped him/her wrong.
Think of it, you could go and do your very best popping job and nothing pops out... FEMALE!!!! yay! So next year you buy a nice big male for "her" and after investing a lot of time and money and doing a lot of research you discover when you put the two together, they combat.... yup, two males. Sh!tty deal.
With popping, people who don't know what they are doing and find that no hemipenes pop out, shouldn't assume it's a female. There is a good chance you just couldn't <b>make</b> them pop out but it IS in fact a male.
Anyway, obviously my advice is get her probed by an expert. But since you're just more curious than anything, post some pics of her tail. There are people on the forum that will be able to give you a good idea...