Cleaning sucks. Your job is to clean toilets and do the most shitty work that people are willing to pay hundreds of dollars not to do.
Client suck. You are going to be dealing with some of the most upity people in the world. They are going to expect things are done to their perfect unrealistic expectations otherwise they will expect a full refund.
Employees suck. People who are career maids are only career maids because they don't have a better option. Usually part of this is dealing with people who are either ex meth/hard drug addicts, ex criminals, very stupid, no social skills, very unreliable, etc.
Margins suck. Cleaning has some of the worst margins out of almost any industry, except maybe food.
Nobody wants to run a cleaning company, which makes it hard to sell. Very few "business owners" want the "job" of running a cleaning company. There are a vast number of better jobs out there that pay more that don't involve such shitty duties. The only real way to sell the company, is if you have a manager in place to "handle" operations.
If it's your first company - go for it. You'll learn a lot. Expect it to be a learning experience. A cleaning company is great if you're not afraid of hard work & are very humble.