Dear one,
This is best:

• Take long life initiation next year.

• 500 long life tsa tsas. You can request the Kopan nuns to do these, or they could be done at Nalanda. You just need to be very careful the holy image isn’t damaged while they are being made.

• Do Amitayus long life practice / meditation. Recite at least 300,000 mantras and do the sessions in the morning. Do this not only for yourself; in your heart think of His Holiness the Dalai Lama and all your gurus, and the Sangha who preserve and spread Dharma. Include the benefactors who support Dharma and all those who do good things for others, and also the evil beings—for them to meet Dharma and abandon nonvirtue, and to adopt Dharma. Of course, include your family.

First complete all the study and the practices above, then check again about retreat.