What is the most logical next event?

How to celebrate your girlfriend's birthday
Pick a date.
If possible, you'll probably want to have the party on your girlfriend's actual birthday. However, if the day falls during the week, it's usually best to move it to the weekend so guests don't have to worry about getting up for school or work in the morning.
You can choose the weekend before or after her birthday, depending on which is closest to the actual day. If you're planning to throw a surprise party, try to pick a date before your girlfriend's birthday.