We can’t tell you how much to use as dose depends on factors individual to you but ballzan’s advice is good and you ought to read the “Finding your sweet spot” post in this thread:
However, my personal feeling is that if it is standard Ammo, one spray on a 24 year old is likley not enough.
And OD is not something to be afraid of - its all part of the process of finding your limits in a range of social situations.