"Then everyone is coming. Good." Maria made a very clear stand so that everyone understood that ehr intention was heading inside the dungeon.
With a driving force behind them, the group didn't have any reason to sit and wait. The time of day didn't have any effect of the dungeon and how it would work for them entering. Therefore, heading in now that the day was shifting to night was actually a better idea.
The group would not have to worry about keeping watch since they would be within the dungeon already. That meant that they would all be on alert. This was also another benefit of being stronger than they should at their age.