I played varsity my freshman year and would recommend this to you...first off you don't have much of a say in the matter...second, i have noticed that splitting the time between JV and Varsity is a good idea as i watched a lot of my friends do that. This allows you to get good playing time (on JV) and second you can adjust to the speed of the varsity game.
I ran track in high school and earned my varsity letter freshman year (top 6 in the county in any event). In my opinion you always want to run against the best. If you've got the talent for it why hang back in a slower heat (all you do is run a slower time). Make sure you keep your expectations in perspective. Good luck!