We did not go to my future dil’s graduation. We knew they were about to get engaged and had only met her family for 5 minutes at an airport once. They had been dating for 4 years. The reason’s we didn’t go were 1) it was a plane ticket for us. 2) Son was studying for vet school finals which were the next week, 3) She already had my son, her parents, 4 siblings and one set of grandparents coming from a couple hours away to the graduation. We met them over the summer this year after the kids got engaged when we already had a trip planned to visit and her parents decided to drive up to see us. Worked out well. I think it is what the GF and her family think is best.