Not at all. If you do not know when your event will start or end, you can work around the start and end time by selecting "Yes" for the "Is this an all day event?" question. This will remove the time fields and you will only have to choose the dates. When you figure out what time your event will begin and what time it will end, you can go back, and select "No" for the "Is this an all day event?" question. This will put the time fields back and then you will be able to provide the start and end times.