i wouldnt worry too much about it, yes you are suppost to change the diff oils and the motor oil but it isnt really going to do anything if he didnt do it while he had it. as long as it is changed sometime soon you will be fine. the reason you change the oils is because on a new 4wheeler there will be little metal shavings that fall off the metal parts, you just change the oil to get rid of the shavings. you are suppost to adjust the valves in the motor too, i have over 600 hiles on my 4wheeler and they are just starting to rattle. the manuel says to adjust them at a certin time but if they are not "ticking" bad there isnt a need to adjust them, if you hear loud ticking then i recomend adjusting them. you said your not too mechanically inclined so i would take it to a friend or the shop to get it done. the ESP is a nice feature, some people like it and some people hate it. at first you may not like it but it will grow on you. o yea welcome to the site, dont worry about asking too many questions on here, thats what this site is for.
-Aaron
-Aaron