I was very active/athletic in my younger years. Rode my bike everywhere. Then life as an adult interfered with me...for 20 years....so here I am and have been trying to get back to high levels of activity for several years. I kayak and hike and do crossfit in my gym but have been up and down. Now adding biking back in and got a specialized sirrius. Love the bike but am so out of form for shifting and found my clipping in and out to be as rusty as can be. Any tips for starting back on the bike for one with more than a few too many extra pounds?