Your relationship with Megan changes pretty much instantly. Whereas before she used to treat you like garbage, now she's infatuated with you, and does anything you want. As a result, you have the double fun of exploring a new life as a girl, and having an excessively hot woman willing to show you the ropes and do anything for you that you want. Anything!
Maybe you won't want to be a girl forever, but it's fun for now, and it's even more fun having your once-dismissive gorgeous roommate at your beck and call, always available for your every flight of fancy. "Megan," you say, "from now on you and I are in an exclusive relationship. You are to tell anyone who asks that we are together, and that you have always been into girls, and that you're only just now comfortable announcing it to the world." You smile and lean back on the bed. "Now come over here and show me more of this hot lesbian action." Megan smiles, climbs on top of you and embraces you in a passionate kiss. You command Megan to commence another round of sensuous pussy licking, which she does eagerly. You love that you set her up to have a real attraction to you. That way you know she likes it, and she'll be even more into it. Sure enough, she brings you to one orgasm after another, and when you're finally spent, you curl up with Megan into a deep sleep, your first as a woman, thinking happy, excited thoughts about starting your new life.
As it turns out, a lot of the details are more mundane than you expected. You have to convince everyone who expected to see your male self that you're a female, and that you had always been a female. You do have the gun, but it is a bit of a pain in the ass using the mind control on literally everyone who once knew you. So you try a little trick. Once you mind control someone, you transform them too, thinking to yourself as you press the trigger that you want to turn them into exactly as they are, except that every time they touch someone else, that person will also believe you were always a girl, to the extent they knew you to begin with. That way, you'll spread awareness of your new female self around campus (and the world) without any more action on your part. A little bit of transformation-gun jujitsu, but it serves your purpose, and within a few days you no longer have to keep pulling out the gun to convince people you were always female.
When you started you wondered about discrimination about your lesbian relationship. As it turns out, your campus is completely hospitable to your lifestyle, and you face no negative repercussions at all. Actually, the only impact you notice on campus about you and Megan is that the dudes all seem to find it unbelievably hot that there are two gorgeous girls on campus who are doing each other on a regular basis. You're less shocked once you think about it and realize that you would have been just as intrigued if you were still a dude, but on a day-to-day basis the attention still freaks you out a little.
And, of course, the sex is fantastic. No matter how often you do the deed, you never get sick of having Megan please you and satisfy your new pussy. You transform your body to have more frequent and powerful orgasms, and you find yourself having sex sometimes upwards of three or four times a day. And whenever you're in the mood for some variety, you go find some dude at pretty much any bar on campus. At first the thought freaks you out a bit, but it is how the female body was meant to be used, plus it just felt satisfying to have your pussy fucked every once in a while. And when it comes to the girls, you don't stop with Megan. Whenever you see a hot chick, you mind-control them into having hot lesbian sex with you, and into thinking that they wanted it all along.
The whole experience is amazing and new, and the weeks fly by. Eventually, though, it starts becoming a little bit unfulfilling, and you're not sure why. At first you think you're sick of being a woman, but right before you turn yourself back into a man, you start thinking about what you'll do with Megan in the future. Once you think of Megan in her mind-controlled state, you realize that it'll never be as deep a relationship as it could be. And now that Megan treats you well, you think you might actually want to have a real relationship with her. You could just instruct her that she will always be attracted to you, both physically and personally, and otherwise she should now use her own free will. Then you'd be all set.
Then you remember why you picked up the gun in the first place. Do you want to have this relationship with Megan as a guy or a girl?