UC apps submitted a week ago. Made mistake...T.T

i forgot to add one of class in my senior year so i wrote letter to
every colleges that i applied to
After 3days… i was reviewing my receipt and saw another mistake made in 7&8th grade and 9th grade
Im preparing another making changes letter…this will be 2nd time sending it
do you think they will think that i am not responsible ? and might affect the acceptance?
im so …worried T.T</p>