The 17-year-old's final score was just 0.75 short of qualification, but Starling feels that she exceeded expectations by making it through the preliminaries.
She told BBC Sport: "I didn't even think I'd make the semi-final yesterday. 0.75 to the final - it's tough when it's so close, but it's my first Olympics so I'm really happy with my performance.
"I really wanted to get over 300. I just aimed to have a really good time and I did."
Fellow Briton Rebecca Gallantry, who came 25th in the competition in Beijing 2008, admitted that she was "disappointed" with her 18th place finish.
"Sport can be tough sometimes," she said. "I gave it everything I had but unfortunately it didn't go my way, so I'm a little disappointed.
"I'm not sure [about continuing]. I'm going to take a break now. It's holiday time and then [I will] look at things for next year."
The final of the women's 3m springboard takes place tomorrow evening.