Its isn't bad, but not best

I get my part time job during this coming holidays.
Got a job during holidays is quite a good things, that better than everyday sit at home, nothing to do..
Last year, I also got a job, feel happy so, cause last year no friend date out with me.. got a job can past my time more easy and still get pay..
But, this year, seem meet more friends got same interest with me. I get many invite to go trip or party celebration.
I'm very happy, and hope that I really can go.. But, now, I got my job, its isnt bad but this will cancel many of my appointments.
I wanna trip and party.. but, cannot cancel my job.
Friends not all of my life, but job also not the most important thing..
Dont know how to cancel all my invitation, cause I hope to attend their invitation, but i cant put down my job and I dont know need to give what reasons to all my fiends.. I know, their plan still can go on without me, I'm not important.. Still, since I got friends that can fulfill what my interest to do, I dont want disappoint them, so that next time I'll get the chance to go so..
So, Got A Job Is Good Or BaD Thing Leh?!?!