I humbly encourage everyone to make giving a larger part of your life. Consider giving at least 10% of your income to cost-effective charities -- because cost-effective charities can do thousands of times more good than merely regular charities. So your $1,000 donation can do as much good as $1 million, if given well. Join others: https://www.givingwhatwecan.org/
I think thinking in terms of percentage of income doesn't work, because the lower your income, the lower a percentage you can afford to give away. I have found it better to think of it as a percentage of your non-essential expenses. e.g, if you spend $500 per month on non-essential things (eating out, movies, netflix, amazon impulse buys etc.), then you can afford giving away 10% of it ($50 per month) to charity.
You didn't get here by yourself. You know some of the people who have generously contributed to you. There are more than you know. The ones who stick out are relatively wealthy. Do you think they are generous because they are wealthy? I submit to you that normal wealth does not make it easier to be generous. A person rich enough to buy a boat has just created more demands on their wealth. A big house usually involves more ongoing financial obligations than a small house.
For most people, generosity is not a function of net worth. It is a matter of character. You can make it part of your character beginning today. You are about to leave my house and face the world on your own. There will be challenges. Money will be tight. "Starving college students" isn't always an amusing tagline. I encourage you to make a point of doing something generous. Maybe commit to giving $1 to a random person on the street every week. Maybe donate plasma. Maybe volunteer to be a Salvation Army bell ringer. But make a point to do something frequent. At least once a month. Even when tuition is due, or rent. Even if just an hour of your time. It's up to you. But do it regularly and relentlessly. If you ever get to where it is easy, it is probably because your circumstances have improved but your generosity has not kept pace.