Possibly going on the pill! Please help 😁

Kayy 💗
I have very long period that last for around 14 days. I think I am going to start taking the pill to regulate them, but I am also extremely concerned about the side effects! I'm worried that I will have mood swings/ my emotions will effect my days :( & also I am worried about what really to expect! How should my periods be when starting the pill? Any advice will help. Thank you all so much ❤️