Dude I really hate to tell you but you're really in for a big hurt. Sorry man, you're 16 and you have more of an attitude than I had. I'm just trying to offer you some advice but you'll learn it the hard way.
Here's some simple numbers for you to crunch. Lawn maintenance pays around $60 an hour out here for a reliable, well established company. I was making $60 an hour with about $7K worth of brand new equipment, I bought nothing used. I spent more on a truck, all together I had about $18K riding around mowing lawns. Now a truck can be had for about $5K easily, I just spent a little more because my work truck was my personal truck and I wanted something fairly nice. Now, not counting the truck, $7K worth of equipment produced $60 an hour. When we got into landscaping, and we have it good for skid steer hourly rates out here, you gotta drop $20K for a new skid steer to get to about $75 an hour. You could buy used, but we're comparing new lawn equipment to new landscaping equipment. Then you have to buy a decent sized truck and a big trailer to haul it around, I won't even get into those numbers, that's just part of the biz, but actual billable hours the mowing route made me more money for less investment. Now let's see what makes more steady income for less investment. Do the math. Mowing isn't a glamor job, nobody ever said it was, but if you manage it right there's potential for big money.
I'm just having a really hard time believing that anyone is going to put big money on a kid doing landscape/hardscape jobs who isn't insured, licensed, or bonded. I can speak from experience on this one, I'VE BEEN THERE. There's so much more to the business than you can even comprehend, especially when you think you need 120 lawns to make any money. I know guys that had 60-80 lawn accounts grossing $120K a year, pretty good money for cutting grass. And getting materials delivered? Not a big deal. If you're really in the landscaping business, no fooling around BS with $3K jobs, would you rather be wasting your time driving to and from the jobsite hauling 3 yards of material at a time for $40 an hour to cover your hauling costs or staying on site with your crew billing $70 an hour for your time? You just don't have it figured out yet, management is absolutely key in this business, forget the equipment because ANYBODY can go buy the equipment. It takes someone smarter to buy the equipment and put it to use effectively, all you want to do is buy the toys and pretend you're a big shot. Efficiency and logistical decisions are what make you or break you. You bid a job and miscalculate the quantity of material. Who pays for it? Not the customer, it comes out of your net profit for the job. Do that enough and you've just worked for free. Lawn maintenance that doesn't happen, there's NEVER a negative day in the lawn business unless you toast a mower or something disasterous.
Do as you please, far be it for me to stop you. But when it's all said and done you'll be out of high school wondering why you're still in this game when you could be at college. You have a lot to learn and by god it'll teach you. I can give you credit for jumping into this stuff, I did, but you will pay a price at some point, make no mistake about that.