Roman 10:9 That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised Him from the dead, thou shalt be saved.
The key here is 'believe in thine heart.' Otherwise it is that simple.
Lukewarm has nothing to do with it, its all about belief (not head knowledge) but heart believing.
There are lots of doctrines and traditions of men trying to change this simple message; the simple truth is stated in the above scripture.
I have a friend who said he accepted the Lord years ago but that was the end of it. Said the prayer and then went back to life as usual. Obiously, it was head knowledge.
The reason I asked what you thought is because I know people who feel otherwise. That just because you say you have acccepted the Lord doesn't necessarily mean you're saved. You have to live it. But if you truly are, the actions will follow.