forgot to say it's pretty common for jobs like this to take longer than you thought they would. that seems to happen to me everytime i do anything like that. that's why i give the ballpark figure because i'm 75% sure it's gonna take a little longer than i'm thinking in my head it will take. this gives you some breathing room so to speak should something come up which usually happens.
an estimate is just that. an estimate. you need to be close to your estimate though and not way over it.
don't estimate $350 and then charge $565. that is way off. a proper estimate would be to tell them it will be in the $400-$600 range. then if you say $565 you are in good shape.
it all comes with practice. the more you do the more you learn and will know about how long things take to complete. the bigger the jobs the harder it is. that's why on bigger jobs i always aim high with my estimate just in case. you can always charge less. the customer will be thrilled with that but they will be upset if you charge more than your estimate.