maybe aslan didn't want to force his way and bruise the poor
kid's ego, and allowed high king peter to depend on his own
strength if he wished, and waited patiently until peter gave up
struggling with his own strength and turned to aslan.
anyway, peter didn't believe aslan was alive and kicking, after
all, he hasn't been seen for 1000 years, and most ppl have
forgotten who he is. thinking that he's just a fairy tale
only lucy, with her child like innocent and trusting heart could
see him, and also, she was the only one who was actively searching
for aslan.
her efforts weren't in vain