thinking about nami's backstory and how she begged for help twice, and both times ended up with Gen getting beat up and sliced to ribbons, as well as the rest of the villagers getting attacked as nami watched in horror, and this was after watching her mother get shot in the head
then later on in arlong park, she watched as several marine ships came to try to help and watched as arlong and the fishman pirates sank each and every one of them before the navy stopped sending help altogether and in just a few hours nami realized that she can no longer ask for help, it won't successfully come without lose of life of either random people or those she cares about
so at that moment she decided that she can't rely on anyone, can't ask for help lest they get attacked, and that she is completely and utterly on her own
and then comes in luffy and the straw hats, determined to help, but i think it's important here to know that luffy waits until nami asks for it, something she was avoiding until arlong backed her into a corner and everyone she loves was about to be killed despite all her effort and struggles
asking for help meant death to whoever would, but not asking for help would lead to the deaths of those she was trying to protect
so she asked
