Depo Shot 💉

My boyfriend and i have had sex before but the second time the condom broke. i took plan b because i wasnt on birth control but i was wondering about if the depo shot is the best option? do you need a prescription for it? how long does it take to fully work as well? can you get it done without parents knowing? and also how much is it? sorry im asking to much questions id just like to be safe and not end up pregnantÂ