Cut 25 minutes off my round trip time in 3 months

Just did my normal outdoor walk, from my house up the hill on Main Rd. N, then loop around at the west end of Old Country Road, then loop around at the east end of same, then back to my house on Main Rd. N again. 4.1 miles. I just did it in 75 minutes, which is about 3 1/4 mph. The first time I did it, it took me 100 minutes, and I was winded and already sore before I even got home. Today, I kept finding myself walking faster on the uphill sections and when I got home I was like, "Maybe I'll get on the treadmill." And I probably will a little later. So, that means I've cut 25 minutes off the total round trip time from 3 months ago when I did that walk the first time. And I never felt totally winded, although I did have to take my scarf off and open up my jacket for a while, but it's hella cold so that didn't last long, it easy to cool down too much. That's totally awesome. I'm really pleased to see and feel such a tangible change in my health and my cardio conditioning. I've always liked walking, especially outside with music. It makes me feel good, and I always have really good creative ideas when I am on a walk.