How to deal with unsolicited pep talks or advice?

This typically happens with family and I will use my brother as an example. We could be having a conversation about say, college, and I decide to consider an elective because I think it will be good for me. He might veer off into a pep talk how I’m fine the way I am and don’t to be down on my self? It throws off the conversation and I’m left confused why he chose to do it midway through it.