Your local network connection is almost certainly 100 Mbps but that is only between your router/databox and other local pcs. Your internet connection is more likely to be 1.5 Mbps-5Mbps incoming and 384 Kbps outgoing.

Its will be hard to say if your actual internet connection speed is sufficient without testing it. Often the speed is sufficient but something called “latency” is not low enough to make video conferencing comfortable, at least part of the time.

If your going to get a router anyway, get a wireless one even if you cannot now use it. Just disable the wireless mode for now. Please don’t lose the password you assign to it during the install. You will gain flexibility you will want later.