I am going to purchase air tickets from JFK to India on Etihad for me and my wife. It gives us 17424 miles each.

The miles required to upgrade to their silver program from their basic membership is 25000.

Will I be their silver member before the starting of the trip or do I get the upgrade only after completing the trip?

I am asking this because silver members get access to their lounge which will be useful for us during the long transit