I think the answer to your question is yes for example with $p_0 = n+3$.
See the following paper:
"Small Representations Are Completely Reducible", Robert M. Guralnick, J. Algebra (1999).
Theorem A in this paper says the following:
Let $k$ be a field of positive characteristic $p$. Let $G$ be a finite group containing no nontrivial normal $p$-subgroup. Let $V$ be a $kG$-module such that $G$ acts faithfully on $V$.
(a) If $\dim V \leq p − 2$, then $V$ is completely reducible;
(b) If $\dim V \leq p − 3$, then $H^1(G, V) = 0$.