By nature, I am not a selfish person. I was not raised to be selfish and want everything for myself. Being selfless is a personality trait that many people take advantage of; it makes others believe you are a "pushover". As the years go by and I enter my 20s, I have come to the conclusion that my time to be selfish is right now.
Your twenties are the years where you discover who you want to be and who you want to surround yourself with. It is time that you stop hanging out with "friends" that are not there for you when you need them to be. It is a time to cut people out if they are not adding happiness to your life. It is time to date and get to know the kind of person you are looking for in a partner. Your twenties are full of mistakes (you are supposed to make them), the key is only to learn from them.
Make those scary decisions and take risks. Be the first and last person in the office. Be enthusiastic to work and learn from others. Do not be so hard on yourself, not every decision made will be the right one. Everything happens for a reason. Take all the selfies and videos in the world! Take in every moment.
I have come to learn that everyone is going through their twenties differently. Some are already engaged, have kids, and have their dream job. Others are still trying to figure it out; regardless of where you are in your twenties just remember to take some time to be selfish. Give yourself moments to put yourself first no matter how hard it is.