Anyone else's mum find Out...?

So recently it was my boyfriends birthday and I posted a Flipagram for it on his facebook wall. There were some photos on there that were kinda hinting we were for example seeing each other naked (pics of him in my underwear) my mum is friends with him on facebook and saw the Flipagram... She text me straight away and was very angry. She saw her bestfriend that day who happens to be the first and only adult I told about having sex with my boyfriend. She swore never to tell my mum. My mum asked her that day if she knew anything. She couldn't lie to my mum so she told her. My mum then sat me down that night and talked to me about how she knew me and my boyfriend were a lot closer than she though (sexually active). She was completely fine with it as she knows him very well and really likes him. I was so scared for her to find out but honestly she took it so much nicer than I thought. She didn't ask me any awkward questions and since that day she hasn't brought it up. So for any of you young girls out there wondering whether to tell your mum or not. I think it's worth it. If she loves you which she no doubtedly does then you should tell her. I went 11 months without telling her. She never had a clue...