There is absolutely no need to retract your foreskin to put on a condom. Nor any reason not to let your foreskin retract and stay retracted if and when it naturally does so.
Any such instruction found in the packaging - or on the Internet - strongly suggests that those who write the instructions are actually not familiar with having a foreskin, but making suggestions on how they imagine a foreskin functions.
The fact is, you simply get erect - and put the condom on. Within a short time you will leak "pre-come" - lubrication - which will allow free movement within the end of the condom and your foreskin will adopt whatever position naturally suits it within the condom.
While people (men, that is,) tend to find condoms somewhat uncomfortable, this will actually be less evident with your foreskin covering your glans, and whatever reduction in feeling the condom (plus your foreskin) causes, is unlikely to slow you down(!) at your age.
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