Pyotr: Do you live with your Mom and step dad? or split time with her and your dad? Is the yard at your mom's house condusive to a small coop and run? Are chickens allowed in your neighborhood? Do you have the funds to support your plans, or will your step dad have to pay for it?
IMO, you'll have to show your step dad that you have the ability to independently take care of your birds, including daily feed and water, keeping their coop and run well cleaned and maintained. Ability to buy what you need for feed. Can you make a coop? Start up costs can be very expensive, but there are ways to decrease those costs. I would suggest that you go to the learning center and down load some of the many articles that will help support your request. Of course there are the benefits: fresh eggs, supply of compost and manure for the garden/yard. Outdoor pets. The down side is the expense, especially starting up. The noise: even without a rooster, hens will be noisy when egg laying time comes around. But... IMO they are not as noisy as some dogs are! You'll have to tend them at least twice/day, and will need a plan in place to deal with freezing water in the winter. Are your family relations such that your dad might be willing to help you get started, perhaps help you build a small coop and run that you could then take to your mom's house?
I will tell you that I started my first flock when I was 12 years old. But, we lived in a rural area, and my dad was a farmer at heart, but not by trade.
While you are convinced that "Buff Orps are the best birds!" (I applaud your enthusiasm and conviction!) You might want to do a little bit of homework in that area as well. Check out "Henderson's Chicken Breeds Chart". What ever breed you choose, be sure it will do well in your climate.