adult onset asthma????????!

As a kid, I never really had any problems with asthma/physical activity. In high school I ran track and cross country (winter track was outdoors and it was very cold, but I never experienced breathing problems)

Over the past couple of years however, I have noticed that running outside, especially in the cold, leaves me wheezing and unable to continue for more than 15 minutes with my jog. Warm weather is generally ok, but I still feel a slight tightness even when it's 70-80 degrees out.

i am wondering if it's possible to develop asthma at 22? I am very healthy and the only medication I could think of that would be a problem is my birth control Yasmin. Has anyone else experienced this? should I get an inhaler? I'm scared it's just going to become worse and worse :(