im 56 and want to do a road race in mid july . For a couple of years i've been riding and always wanted to try a race . First i wanted to do time trials but i wasn't able to do them due to family comitments . Then i went to a couple of training races and got lapped. after being lapped a few times i knew i wasn' very good . For the last 5 mos. i've lost 25 pounds practiced bike handling drills and do various intervals 3times aweek along with recovery rides and power lifting for my legs. i do a weekly tt. of 10 miles on a flat but verry windy course . my 1st goal was to do 17 mph in the large ring and the smallest cog it took a couple of weeks now im inthe large ring and small cog and avg 20 mph for the 10 miles. my question is what gears do i use for this race ? because ikill my self in the hardest gears and im hopeing by using different gears i will be faster and less beat. help