Hello, sadly new servers will not be able to participate in cross server events until they reach a server age of 60 days, you could always try to ask your friends to join your server so everyone can participate in these events in the mean time!

minimum register needed 23 or 30 players i think but we dont have that much player only 10 max 15 cant u change minimum requirement to enter sage?

I can ask about getting the requirements changed, but it is not likely to happen. Do you know of any other players that might want to join your server to help you out? You could always try that route.