Yes you can definitely have sex with her. The very first women of your life, the very place you came from, the very first women you meet and interacted with. Ever man develops sexual feelings for a women who they know from a very long time.

Their mother on the other hand is also the same, many guys have crush on their mother. If she is ready to have sex with you, then you should definitely have sex with her once I your life.

As also being experienced one you can also learn many things from her. And this not our fault for having sexual feelings for our mother. She came out infront of us, half naked, in seducing manner. So if your mom agrees you should have sex with her. It's my opinion though.