In Act 1, why is Viola willing to demean herself to work for Orsino?
I'm not sure if it's because she already loves Orsino beforehand (If she does, please explain how and why), or that she needs money and therefore works for Orsino, and then falls in love with him.
Viola is a well-born maiden who has been shipwrecked in a foreign country. She needs to look after herself, obtain money, and find news of her brother. In this period, it was completely unacceptable for young unmarried women of her class to appear alone in public; had she done so as a woman, she would have been mistaken for a prostitute, or possibly raped. By getting a position as a page, she manages to stay within the social circle of the nobility, earn a living, get the protection of the ruler of the realm, and continue to seek for her brother. Moreover, being a page isn’t really demeaning – it’s a position in which young noblemen can learn the manners of the court.