It is extremely rare for there to be medical evidence 10 years after experiencing sexual assault, rape, or sodomy although it may depend on a number of factors such as the type of assault, the age and health of the victim, and whether or not evidence was collected at the time of the assault.
In cases of sexual assault, physical evidence such as DNA or semen can sometimes be found on the victim's body or clothing, and this evidence may be preserved for years if collected and stored properly. Additionally, injuries sustained during the assault, such as tearing or scarring, may still be visible or detectable through medical examination.
The optimal time frame for evidence collection is within 72 hours of the assault to be able to collect as much DNA evidence as possible. However, a kit can still be useful in gathering evidence after this period, up to 7 days due to advancements in DNA technology. After this window of time,  only the physical and medical treatments are possible and evidence on your physical body cannot be gathered.
However, it is important to note that the absence of physical evidence does not necessarily mean that the assault did not occur, and many victims do not report the assault or seek medical attention immediately after the incident. It is also common for victims to experience psychological symptoms such as anxiety, depression, and PTSD, which may persist for years after the assault and can be considered as evidence of the trauma they experienced.
It is never too late to report a sex crime - either adult sexual assault or child sexual abuse - to the police. A person can, theoretically, be charged and convicted years or decades after the alleged acts depending on the statute of limitations in your area. You also do not necessarily need medical evidence to report.
But realistically, the longer the wait between the incident and the investigation, the more challenges you may face. For example, some survivors are wary of being cross-examined at trial. Where there has been a delay in reporting, this is almost always used as an avenue for the defence to question the credibility and reliability of the witnesses, including the complainant.
In recent years, the laws in different jurisdictions have seen some improvements to how historical sexual offences are prosecuted. For example, if the complainant told a friend or relative of abuse around the time it occurred many years ago, that friend or relative can be called as a witness to recount the report.
Only you know if reporting is right for you. Be gentle with yourself, but remember if it would help you on your healing journey, it is never too late to take action.