Nice!
Leave the heart-rate monitor and home and go have fun!
If you think about it in terms of percentage increase, it is not a small increment. Also, everyone starts somewhere. As long as you start and keep going, it doesn't matter. When I started two years ago, I was wiped out and proud of myself after a 6 mile ride. Now I knock out centuries with no problem and am on a racing team. Before you know it, that loop is going to just be a warmup.
I stand and rejoice every time I see a woman ride by on a wheel...the picture of free, untrammelled womanhood--Susan B. Anthony