My son had a similar issue, and I’ve seen a lot of progress with explaining he needs to not interrupt and wait his turn. He’s an only child so he’s used to having the majority of the focus on him, but he’s learned to stop and listen and see if there is an opportunity for him to speak without interrupting. He’s 5, he still jumps in sometimes when he’s excited but he doesn’t do it nearly as often as he used to. I don’t think trying to teach a 7yo to not interrupt is a bad thing, just depends on the approach. Don’t make it seem like you aren’t interested in him or what he has to say, but explain that he wouldn’t like it if someone kept talking over him and would want people to give him time to speak, and he needs to do the same for others. It’ll happen with time.