We study the probability distribution P(H, t, L) of the surface height h(x = 0, t) = H in the Kardar-Parisi-Zhang (KPZ) equation in 1 + 1 dimension when starting from a parabolic interface, h(x, t = 0) = x 2 /L. The limits of L → ∞ and L → 0 have been recently solved exactly for any t > 0. Here we address the early-time behavior of P(H, t, L) for general L. We employ the weak-noise theory -a variant of WKB approximation -which yields the optimal history of the interface, conditioned on reaching the given height H at the origin at time t. We find that at small H P(H, t, L) is Gaussian, but its tails are non-Gaussian and highly asymmetric. In the leading order and in a proper moving frame, the tails behave as − ln P = f+|H| 5/2 /t 1/2 and f−|H| 3/2 /t 1/2 . The factor f+(L, t) monotonically increases as a function of L, interpolating between time-independent values at L = 0 and L = ∞ that were previously known. The factor f− is independent of L and t, signalling universality of this tail for a whole class of deterministic initial conditions.