Why did I feel frozen up or nervous when I saw a hot girl when I was riding my bike in public?

[Matt]

I was riding my bike around in the streets and I saw a hot blonde girl wearing sunnies and perfectly dressed I didn't want to ride straight passed her I was slowly riding I think I didn't want her to see me or something am I shy or what I bet if I talked to her I'd still be nervous,I didn't know her tho it was in a public so she was a hot stranger how can I overcome this feeling,I mean I rode off later passed her acting cool going full speed but I don't want to act cool anymore