Yes! We encourage you to go ahead and post even if the time has past. All you need to do is log the meal, activity, or note and adjust the time.
Meal Log
Here's an article to walk you through meal logging: How to Log Favorite and Recent Meals
Activities Log
Here's an article to walk you through logging activities: Logging an Activity
Note Log
Here's an article to walk you through logging notes: Logging a Note