What is the correct preposition to use with ambitious?
- I am ambitious to achieve success.
- I am ambitious about achieving success.
As ambitious is an adjective, it rarely needs any preposition at all.
An ambitious man.
If you must have one, 'of' and 'for' are possible but also obsolete.
In your sentences, "I am ambitious" would cover it, or "my ambition is to succeed/achieve success"