I taught my students last year that the age of consent is ten years, when the case of Ese Oruru came up. This is the case of a teenager who eloped with her boyfriend to Kano kn Northern Nigeria. The boy got her pregnant and the authorities were at the neck of the boy, that he defiled a minor. Ese was only fourteen years then. I thought about it and remembered that at ten years, men had started making advances to me, and I shunned them. I then used it as an example to my students. I told them that a little girl who will shun sweets, ice creams and meat pies from male admirers will say no to having an affair with that boy. A valid index to the age of consent should be as from ten years up...Any girl who is above ten and consents to a man having carnal knowledge of her should be seen as an adult who has consented. This is because a ten year old girl already knows what is sin and what is right.

age of consent to what bondage of actions, by following/leading/imitating what sort of social relationship might be formed in the process. that's the beef, is it not? 

Can 6-yrs old operate a motor-vehicle? be a movie star on his/her own terms... it's always case-by-case in 'genius' grades, right?  "a 10 yr-old girl knows what is sin and what is right? " That also depends on her cultural upbringing... if she sinned, what's the recourse? 

OK.

I accept that this age differs in any country. But as an educated person, Do you think 18 is a suitable age for this purpose?

I think it depends on the culture and the rights and responsibilities of a person living in that culture/country. If a culture expects their people to have increasing responsibilities at an early age then possibly the age of consent should be lower because the culture demands an individual to do more and therefore know more about the life around them.  If, on the other hand, the culture allows a person a longer time to achieve maturity then I think 18 is a reasonable age to grant consent. I do not agree with the opinion that 10 is the age of consent for a girl.

Culture is relativistic, right. But know you that rationality is the same everywhere. Being ethical is a virtue and should be admonished irrespective of race, birth or class. Remember that no rational culture will teach its nationals to take away their lives as a panacea to getting a good after life. If you command a ten year old girl to jump into a river when she cannot swim, watch and see what she will tell you. I think you will receive an absolute no as an answer. Tell the same girl again that you have prepared a sumptuos lunch of fried rice and chicken in your house for her. If she knows you, she will follow you to your house to eat the lunch. From these two examples, can you not see that she knows what is right and what is wrong. So also is the age of consent. Even if your culture imposes responsibilities for you at an earlier age, I stand my ground that the age of consent is ten years. Any girl who agrees to a man to have carnal knowledge of her at above ten years gave her consent to that,

Yes I think 18 is a valid index. In the US age 18 has been used for a long period of time.  However, there have been times when the social data indicates that an age level concerning a particular matter should be adjusted, An example of this is during the Veit Nam war the voting age was changed to 18 from 21. Young people were drafted into the war.  The feeling at the time was "if we ask young people to service and post pone their lives or even give up their life they should at least be able to vote."  My point is that when there is evidence that an excepted norm no longer is logical or the society has changed in a particular way the norm should be adjusted.

 Is there any inhibition about 'too old to be fooling around' regulation in society? that's not called 'consent' but suicidal intent ? 

The age of consent in most countries is not a marker or indication of maturity.  It is  a legal marker. Unless one shows  diminished capacity then the courts use age as a legal starting point.

When I write consent, I mean mutual agreement to bedmate with a man. It is a legal marker. This legal marker excludes rape of a minor by the menfolk. This act is a criminal offence and the culprit is liable for punishment by a court of competent jurisdiction in the state the act was committed. There are brothels and sex workers who offer social services for money. They should be patronized by rapists and not innocent children who are not yet matured for sexual activities. Such offenders should face life jail with hard labour  to serve as a detterent for intending offenders.

Different people mature at different rates.  Any legal line will therefore be somewhat arbitrary,  All we can do is to hope that the LGBTQ+ alliance doesn't drop the other shoe and add pedophiles to the list of oppressed sexual minorities.   The loathing that even sexually liberated people fell toward sex with children would then be counted as pedophobia (to coin a word).