Slutty jo aged 18.. what she did

After leaving college one lunch break we were on our way to town.. i asked my mate to come so we walked to his house.. he wasnt ready so he said he will pop upstairs and get changed.
As he did this my slut pulled out my cock and suck it untill i spunked in her mouth and she swallowed.. my mate came downstairs and he had no idea what had happened and all 3 of us went out.
Thinking back now it was a council house so it was very small she had no idea who was in the house.. he shared with his brother and parents.. what if someone was in the kitchen or he quickly ran down stairs as i was cummin in her gob
Crazy to think she done that and 2 month before she claimed she was a virgin??
Whats ya thoughts on this? Is it normal behaviour.. any questions just ask

Thanks