It's all been said before mate, but without experience, you'll find it hard, if not impossible.
I did the same thing, was so keen to get into the industry that I looked at getting 'qualified' off my own back and just starting up. Qualifications and courses will help, and you'll learn a lot, but it won't make you a pest controller.
I worked for Rentokil for several years, and I recall being nervous going into different jobs that I had no experience of. Fortunately, I had the most experienced team in the whole company around me, and had a wealth of knowledge and experience to call on,