Am I selfish

Do you think I’m selfish for offering to help provide milk for my friend’s babies(she’s having twins on October) if needed but having to go back on it because it won’t work with my internship. They’ll only allow me pump breaks up to 18 months(my son will be 9 months when I starts) and after I’d pretty much have to fight for it and risk losing the internship as they really don’t need me more of I need them. But it’s really what I need to put my foot into the door for getting a job at the end of this year so I can’t risk not having it as it’s training I didn’t get during online schooling. I planned to wean my son around 1-1.5 years old so not being able to pump during the day won’t affect my son but I won’t be able to keep up a supply to help with twins if I can’t pump every 2-3 hours as I only get 2-6 ounces every time I pump.