It sounds like there is a voltage drop in the starting system.
Turn the headlight and interior lights on, and while trying to start it, observe the lights and see if they go dim or out......Let me know what happens.
That is a sign of poor connections or a dead battery.
First check the battery cable connections, look on the INSIDE of the cable ends where they contact the battery post and make sure they are nice and shiney. If it still wont start, replace the battery and when it starts have the charging system checked to be sure the battery is being charged.
This will get it started.
If you have further questions on this, please feel free to reply. Thanks for asking!