You'll never achieve your desired goal (a portfolio) if you don't shoot, right?
It's much better to start with friends, relatives, etc. who will be more eager to help you out, forgive any mistakes you make, and allow you to do things like, for example, shoot their "bad" side that a future paying client might not.
Start with natural light, since, well, natural light is free. All you need is a well-placed window and a semi-sunny day. Once you get comfortable shooting in natural light, try a one light setup, then a two. It's about learning to see visually, and learning to see, move, and respond to the light. Start small then build up as you see fit.
One more thing. They say sharks smell fear, and the same thing can be said for your willing subjects. If your model senses your apprehension. nervousness, fear, whatever you want to call it, they too will become uncomfortable which will result in less than optimal shots. So take a deep breath, relax, and make your model, be they friend or stranger, feel at ease.