A first timer should NOT try to turn a rank, half grown steer into a 4-H project!
SOMEONE WILL GET HURT! and badly!
For 4-H you have to do the paperwork.
One of the aims is to teach kids that are future farmers exactly what it takes to turn a baby animal into a production animal. Whether it be a chicken raised for meat, sheep, pigs or steers, they have to have the records showing from when they are a baby to showtime that basically teach what it takes in feed and effort to get an animal to market quality. So whoever told you that you can take an almost adult animal and put a halter on it and take it to the show is not giving you the right info. You can take things like that to an open show or County Fair, but not as a 4-H project.
But the main thing is that this animal is not safe. Cattle are NOT like horses! You can take a horse that has been raised in a pasture or turned out for years and with a little patience and TLC you can have a good ridable horse, but cattle are wired differently, they just cannot be tamed after a certain point. They have no urge to please humans unless they are hand raised. Even then, without proper handling they can be dangerous. At this stage, even if you got him halter broke, he would be a time bomb. If something scared him, or got him mad, he would take off, or charge. If you get them young, they learn to repect you before they are big enough to push you around.
You can't treat them like pets, becasue they will hurt you trying to play or if they are in a bad mood. We had a bottle raised steer that we had to sell becasue someone thought it was cute that he would but you when he wanted his bottle. I told them not to let him, but when I wasn't around, she would push his head to get him to butt or charge. Very cute when he weighed 80 lbs. NOT so cute when he was 800!