To the girl forcing herself to be an extrovert, don't.
As we grow up and mature, we are on a long, hard path of self discovery. We find out the type of person we want to date, we find out whether that person is a guy or a girl, we find out things that make us tick, we find out our study habits, etc. One of the most important things we understand about ourselves is whether we are an introvert or and extrovert, what that means, and how we should handle knowing this information about ourselves.
I am introvert. I'm not part introvert. I am not an introvert only when I don't feel well. I am in introvert all the time.
An introvert is a person who is more concerned with their internal thoughts, feelings and emotions rather than external noise. We are sometimes considered shy (most of us aren't) and we are energized by alone time (for a little personal commentary, being a little anti-social makes me happy).
With all of this being said, for whatever reason, I tend to have very extroverted friends. For a long time I lived my life wishing I was an extrovert and often times, forcing myself to be in a unhealthy way.
I would drag myself to these huge house parties jammed-packed, shoulder-to-shoulder, that would completely drain me. I did not have any fun at these parties. It didn't matter if I was drunk or not. I am not anti-social, but I've learned these jammed-packed parties are not my thing. I prefer smaller gatherings of people who I am closer with and feel safer with.
I wanted to be that girl who would jump up on the table and start dancing so badly, but that's not me, and never will be. I had this idea that guys are attracted to the girls who are out there and the life of the party. Maybe some guys are -- but how silly of me to care about that. If a guy is into a girl like that, why would I ever be attracted to him? We obviously would not work out. He needs a girl who will stand up on the bar and dance, and I need a guy who comes over for a movie on the couch.
Unrelated to relationships, we have to take care of our well-being and recognize what recharges us and keeps us going. Extroverts feed off of other people's energy and being social keeps them going. As introverts, we need to give ourselves alone time and time to recharge by ourselves. "Let me recharge my introvert juices!"
We should not over-extend ourselves either. I went through a phase where I was seen as a flaky person. I'd say yes to plans and then bail at the last second. I did this a lot with after work plans. I'd make plans to go out with people after work, and then when it came down to them I would cancel. I wasn't doing it to be flaky. The work night just mentally drained me and being around so many people emotionally exhausted me--I couldn't fathom going out after work at that point. I've leaned now to not make any promises I can't keep. Instead I will say "I'd love to go, but let me see how the night plays out and I will let you know for sure. Could be an exhausting night." This works extremely well.
From the girl who no longer tries to be an extrovert, be yourself. Understand yourself. Take care of yourself.