First time trying to buys some seed corn, man this stuff is crazy complicated.
100-115 day Maturity range depending on where you live in Iowa. 100-106 up north. 106-110 in the middle 110-115 in Southern third. This is just a generalization.
Secondly get a BT traited corn and a Roundup Ready Liberty Link traited corn if you are putting it on bean stubble and or old pasture ground.(Also nicknamed double pro) This protects you against corn borrer and allows you to spray Round up and liberty chemicals on them with no harm to your corn.
Go with a Smart Stack or Triple Stack for Corn on corn scenarios. (These have rootworm traits in them that kill rootworms)
Its really not too difficult just make sure whoever you get it from doesn't hose you on selling you traits you don't need. Also all brands are generally good. My post is just a generalization id say 75% of what people do.
Next know your land- If your farming in the goat hills of SW IA with a low CSR rating go with more of a workhorse hybrid - your not going to need the racey high yielding profile on your ground but it will always be standing and will adapt well to the variety of conditions. If your farming in the flat ground with high CSR go with a racehorse as you can really take advantage of a higher yielding hybrid.
This is a quick run down, anyone that works at the local Co-op or seed dealer should set you in the right path - just remember do not pay for traits you do not need!