Some of the best eating animals that we've processed have been three year olds that have been on grass...have to like the taste of grass finished beef.
Follow Dun's advise...and don't over-cook and if you have never butchered a lean animal off grsss, the fat will be yellow and the meat will have a nice beef aroma and will be a bit darker red than what some folks are use to.
Hanging and processing is as important as the carcass...don't cut the hang time short.
And that's just my two bits worth....DMc