I am a governor, but not a parent goveernor. Many years ago, I ran courses for parent governors though as part of my job. It is quite a difficult role. I agree with much of the posts above. Do not become a parent governor if you want to promote something for your own child, eg your child has SEND and you are campaigning for them to have more TA time. There is nothing wrong in ensuring all SEND children in the school make good educational progress. You need to be able to challenge the Head in a friendly and supportive manner, so do not go in"all guns blazing". It is always worth remembering that most schools fail Ofsted inspections on the teaching and learning element of the inspection. To get a flavour of what Ofsted are looking for in a governing body, have a look at their seb site and the Ofsted Inspection manual.
It takes a lot of time and doing training is absolutely vital. I have noticed that the attainment and progress data has moved on so much from my previous experience of governorship. Think about what skills you have to offer. Are you interested in the quality of teaching and learning, data interpretation, school finance, premises, health and safety, SEND, Pupil Premium children, HR and performance management and are you willing to train for one or two of these roles in particular if you are not up to speed?
You must remember that you are not a parent advocate in the sense that the parents cannot tell you how to make your decisions and you do not have to canvas for opinions before or after decisions are made. You can of course listen to parents, but the whole governing body should do this, not just you. It is highly unlikely that any governor or the head will do something that outrages the parents, but you must remember that you support the decision of the governing body in public, even if you do not totally agree with it. If it is a deal breaker for you, then resign.
Being a governor can take several hours a week, or several hours a month depending on your willingness to visit the school and get involved. Governing bodies have committees and these can meet once or twice a term as well as the full governing body meeting once a term. School visits and training will take up more time. An iminent Ofsted inspection also ramps up involvement.
I strongly believe everyone has something to offer and your school should have an induction pack for new governors and help you settle into the role. Most people find it can take several meetings before they feel confident. Your LA should offer induction training and this gives you a chance to meet other new governors and experienced trainers so you can ask questions of them. Lastly, go for it!