Is it permissible for me to be circumcised without my family's knowledge, if the opportunity arises, given my extreme sensitivity to sexual stimuli?

Marriage, fasting, and staying away from influences are all things that help curb lust, and circumcision is one of them. If lust can be refined without circumcision, it might be preferable to avoid exposing the grave nakedness (awrah mughallazah). However, if there is a need for circumcision, there is no harm in it, even if without the parents' knowledge. Circumcision according to the Sunnah (definition) of the Prophet, peace and blessings be upon him, is recommended, and Pharaonic circumcision should be avoided.