While others have given find advice I don't know that most of
it is right for a 14 year old making his first short film. I suspect
not one of the people offering advice cast their first film from
casting websites when they were 14 years old. Nor did they
pay for gas.
I don't really know what people would be wanting.
What the others have said is right - actors want to be fed and
given gas money. That usually means spending more money
than you have if that's the direction you choose to go. As
ahennessey said, you need a shooting schedule that you stick
to; shoot dates, locations, call times before you put out casting
notices. Then you will need to hold auditions; a place to do it,
some refreshments, at least one other person to help you. Are
you ready to that? Can you afford to do all that for your first
short film? As soon as you step outside of your circle to reach
out to people you don't know there are some expectations. If
you fail to meet those expectations you risk looking less than
professional. And right now, at 14 making your first short you
are not professional.
So I go back to my original advice and now that I have read
your script I have further advice; write a script that uses your
friends and then use them. Overcome that difficult challenge
and make three of four short films. Show people you can actually
finish a few short films. As you do that work on your current
script to make it better, to make it interesting to older actors.
Then you will have a track record as a 14 year old director who
isn't all talk but actually makes movies. Then you can branch
out to actors and crew who are more serious.