So it sounds like it was a group conversation which brings in group dynamics. Normally, in a group I find that there are some dominant people and some quieter people. I try in conversations to make sure that if someone who is quiet or who cannot get a word in and who clearly wants to say something then I tell the others to stop talking and say 'so and so wants to say something'. If there isn't anyone in the group who does that then you need to be a more assertive. Now depending on the group and how well you know them you could say 'shut up and let me say something' or you might find you just have to speak over people to make your point or start speaking at the slightest pause and keep going. This group, do you normally hang out with them and how well do you know them? Because that will make a big difference in what you can get away with. If there are a couple of particularly dominant people then you will need to be assertive otherwise they will just railroad you (and anyone else). Are you naturally a quiet person (like shy)?