It sounds to me like you're riddled through and through with guilt that shouldn't even be on your mind.
Number one, your father and uncle should NEVER have exposed children to pornography. You were exposed to material of a nature that you had absolutely no capacity to process properly and that laid the foundation for a warped view of sexuality and apparently lead to experimentation that you also had no tools to deal with properly at the age you experienced it. Being exposed to that material and those conversations was not your fault or within your control, and you must not let that cause you guilt. You must also recognize how that far-too-early exposure has tainted your ability to explore and process sex and sexuality since then.
Number two, with or without that exposure, it is likely that at some point during adolescence you would have explored sexual feelings and actions naturally. Did you know that some toddlers learn to masturbate while they are still in diapers and do not yet even understand what their genitals are? This has nothing to do with sex and everything to do with exploring their own bodies and responding to naturally pleasurable feelings. There is nothing dirty or corrupt about these explorations and they are ultimately just as innocent and natural as a child exploring their own nose or elbows. What you did with your cousin(s) at a young age may well have been (and likely was) at least somewhat a result of your early exposure to sex, but not entirely so.
The only thing in your story beside your present problems with processing your experiments and feeling guilt is your use of the term "molested" and the age at which you were when this occurred. Can you explain exactly what you mean?