How to approach overbearing mom about new guy I've been dating?

I've been dating this guy behind my mom's back. This guy and I want to take it to the next level and start being alone with each other. The only reason why I've been able to date this guy behind my mom's back is because my dad has been chaperoning the dates. I'm a 20 year old girl and I don't have a car or a drivers license. I can't get out on my own. For these reasons my parents are at least somewhat involved in everything that I do. I also live at home and I am a college student. My mom can be very overbearing and overprotective. She is very difficult to approach and talk to. I tried approaching her about this guy once before and things in my life got turned upside down. She had a very bad reaction to what I said to her. I found out as of recently it was because of the way I approached her. My dad is supportive of me and he is on my side. My dad has done everything he can to help. My dad says that I can't put her "on the defense" when I approach her. This is a big problem that I have with her and I find it very hard to communicate with her. My dad said that I have to tell her about this guy that I am dating because he doesn't want to take the risk of letting me hang out with him alone behind my mom's back. My dad said that we have to basically start from scratch and I have to have my mom meet this guy. This guy that I am dating is very nice to me, he's one of the nicest guys I've met, and he have a strong connection. However, we both find ourselves feeling frustrated because of the family politics. It's impacting our relationship. I have been able to date a different guy with my mom knowing about it before. My mom had to meet the guy, she got to know him, and then we got to out by ourselves. For some reason when I try to do the same thing now with a different guy, she does not respond to it well at all. I've had to lie to my mom a lot because she is so uptight. I've basically had to live a double life. Another thing that may be contributing to the problems that I'm having is that this new guy is different. He has long hair, he has more art related hobbies (he was an arts student), and he is more like me because I'm different too. I would consider my mom to be conservative and I think that these things about him would turn her off. Like I said, my mom is very overbearing and she likes control. The other guy I dated (with her knowing about it) was more laid back and conservative. So I think that made it less difficult to talk about. (This newer guy I met is more compatible with me and we have a lot more in common. He's a better match for me overall.) Sorry about the long story, but I would just like some good advice and some communication strategies I can try on my mom to make things better. I have a very big problem on my hands, it is very hard to deal with and very stressful. (I've known this new guy for like a year already.) My mom and I have a lot of differences, unfortunately I don't think she can learn to just accept it and move on. One suggestion I've already gotten for this problem is to just be straightforward with my mom, keep it simple, and just tell her. Like I can't come up to her and just say, "I want to talk to you" because that puts her on the defense. Any more suggestions would be greatly appreciated, thank you.