This is an important question - and there is no one easy answer.
You love photography, you have your first DSLR camera, maybe some lights, reflectors, backdrops. You have invested in learning - through a multitude of educational sources.
But when are you ready to "charge" for your work?
First, loving photography, and making a business out of it are two completely different things. Just because you love to create, does not always mean you should be in business for it as a portrait or wedding photographer. A lot of people simply want a creative outlet - a way to express all the creativity that is living within them. THAT is awesome and to be applauded.
If you are unhappy in your career, or you are a stay at home mom looking to make some money on the side, you might be looking at this as a way of earning some money, supplementing your income or financing your life.
Things to consider.
1. There are a GaZillion "photographers" that have a good camera. This does not make an artist or a good photographer, contrary to some beliefs.
2. Like college or university, you do not have the knowledge about this career, industry, until you fully educate yourself. Like doctors or nurses, you need actual "hands on" practise for an extended length of time, before you are remotely ready to charge anyone for your talent and skill set.
3. Investment - ah yes. As with any career, you have to make a huge investment in this to succeed. I am not talking just equipment, no. That in and of itself is pricey, but I do think you can get away with an okay body, as long as you invest wisely in your lenses. I'm talking education. You need to invest in your education, and by invest I mean time. Hours and hours and hours of time spent shooting, learning about light, natural or artificial. Creative portrait work is not just in the edit, you MUST know your equipment through and through. If you don't know the capabilities of your gear, you cannot produce the most amazing images. Post processing and editing is just another component that, if you choose to go that route, takes on its own time requirements.
4. Proof is in the pudding. Do you have a website? Do you have a gallery or body of work that is consistent and easily reproduced upon request? Do you get nervous before, during or after your photo session? Are you confident in your ability to produce a product that not only you are proud of, but your subjects are madly in love with?
5. Research. Once you feel you have all the tools to start charging, make sure you are well aware of "what" you are selling. Make sure you find out what professional labs you want to work with, their pricing and delivery structures, and how to charge for your time and talent on top of them. There are a gajillion resources for professional lab products, and much debate over being a "shoot and burn" photographer versus a print photographer. Are you a member of your professional association? If you aren't you should be. The www.ppa.com The Professional Photographers of America (regardless of what country you live in) are the most welcoming and helpful association I know. Not only do they have forums and tutorials to further your education, but they also have print competitions that will help with learning to be a better photographer.
So here is the bottom line. If you are serious about making photography your life's work, and career, you need to research. You need to find out from local photographers that are successful - what their journey has been like. Talk to people, learn from others. Like anything worth doing, or having, this is NOT easy. It is especially not easy with the industry being so saturated. So do your research first, and find out from a monetary standpoint if you need to keep your day job and use photography as an enjoyable creative outlet. Remember, there is nothing wrong with that either, and I think if you asked a lot of "professionals" they would say that they wished they could have kept this as an enjoyable hobby instead.