I can tell I'm getting into shape

Last night I went to the gym to use the elliptical machine and was able to go for 25 mins with no problem, and my heart rate didn't go above about 167. 
Previously, I was ready to quit after 15 mins and my heart rate would be in the 190 range.  I felt great after 25 mins and had somewhere else to be or I would have kept going for a little while longer.  Looking forward to going again!  Taking today off and going again tomorrow.