Is it beneficial to be the first speaker in a group discussion?

It’s a high-risk, high-reward approach to be the first speaker. It will go in your favour if you can make a strong opening remark that is topical and sets the tone for the GD. If you do successfully, you may be promoted to the group leader. If you muck it up (by speaking for the sake of speaking, without truly having anything to say), it will be remembered and will work against you.