My whole family applied for Schengen visa about 3-4 years ago and our visa was rejected and they said they are not sure of us returning back. (By the time we have traveled only to one county)

Now I'm trying to apply for UK- student visa where I have my universities and funds sorted, but the visa agent is asking me to take a new passport since there is chance that my visa would get rejected as the Schengen visa rejection seal is on my passport.

I do not want to take a new passport and fake my Schengen visa rejection. Please advise.