Invisibility isn’t my Prefered Ability
Nothing has changed. I'm already used to it, I've been an invisible background-ish character for most of my life, three weeks of 100% invisibility wouldn't affect me any more than the 80% I was at before. I've once went a full week and a half - after losing my phone - having no contact with friends or distant family, and I doubt more than two people would have noticed had I not informed them.
I couldn't count how many times I've been home while my mom thought I was out, or out and my mom thought I was home. Or the times when I've been stranded somewhere thanks to bad bus schedules, a bad phone battery, and no one was any the wiser. Then there's the times I've strolled into my home kitchen and scared the heck out of my mom thanks to my unintentional soundlessness. It's gotten so bad that I've had to purposely shuffle or stomp my feet in order for my presense to be sensed.
At work, my co-workers either don't notice when I arrive or don't see or hear me when I say and wave my goodbyes. At school, I'm a back-row, loner-corner kind of student; I could think of only one prof who might notice and/or miss me if I turned invisible.
With that said, its not like I wouldn't use this new ability to have some fun, at least for week one.
I could haunt some sucky human beings, torment my sister or my cousins at their schools, climb places I'm not supposed to climb, jump on the back of a pickup truck, maybe sneak onto a plane to Japan (though this would be really, very difficult), or I could hypnotize a pretty, ponytailed, gamer guy into falling in love with me using strategically placed pictures and the occasional whisper of my name bwahaha.
Though, I'll admit, all this stuff would only be in week one, I'd probably lose interest soon after. Oh, and unless my clothes could go invisible too, none of this would happen.