I think it's not good to be selfish because thinking about yourself alone can fail you in some way, being selfish is very bad. if a mother gives birth to a baby she thinks more about what the baby will eat than her.
So I think you not being selfish is good in some ways, let's say if you are a leader or head of the family when going to work in the morning you will be thinking about what your wife and kids going to eat before you think about your own stomach. If you show being selfish to someone and later will be needing his/her help how are you going to ask for help, so I think you not being selfish is good, it opens so many doors for you unexpectedly. A good person thinks of others first no matter how the situation is.
It is good and a blessing to give than to receive. The bible even said do good to others what you want them to do to you, because what goes around always comes around. You don't know what is ahead of you in life. Time changes so if you do good, you do for yourself, you reap what you sow. If you throw bread on the surface of the water you will definitely get it in the future. Let's use the Good Samaritan in the bible when he saw the injured man on the roadside he didn't be selfish but rather helped him.
When I was in senior high I was having so many friends and I was good to them. Sometimes they don't have money to buy food and I give the little I have to them to buy food and eat, I was being good to them not knowing I was doing good to earn something in the future. We completed from Senior high school and didn't hear from each other again for years. Life became hard and what to even eat was a problem for me.
One day I was there thinking about myself and saw a foreign number calling my cell phone and I was surprised. I answered the phone and it was my old friend way back in senior high school. I was really happy and he told me he is sending me some money, I was broke at that time. So if I was selfish the time we were in school and also don't think about those around me I wouldn't have got his help, so I think it's not good to be selfish but From Ayn Rand perspective been selfish is important in some ways because sometimes you regret been good to some people. They pay you good with evil so I think Ayn Rand opinion is good. But on my side not being selfish has really helped me a lot.
@brightacg