Is it difficult to be admitted into the Linguistics and Psychology major at UCLA as a freshman?

I was looking at the transfer stats and saw that the average gpa of those admitted was 3.4 and I’m just curious

No more difficult than any other major in the College of Letters & Science. If your major is in L&S that’s all they care about, they don’t take your major into account for admission decisions. See the “Freshman Selection” page on the UCLA admissions site.