The best place to begin is local community colleges or universities, since you will almost always learn more from an in-person course. If that is not an option, look for courses online that specify what they will teach you so you know exactly what you will be learning, and if it will be time and money well spent. Determine if the wedding photography courses offer any sort of certificate at the end to show to potential clients.
Yes, wedding photo is very important. Due attention should be paid to it. But I think I will prefer to fetch a professional to assist me. It's too time-consuming to learn it. But it's a good way to develop interest.