Nope, she doesn't. This is your choice.
Some things I'd think about with that, to hopefully help you make your own best choice with this, based on what you posted here are:
• What are you scared she might say? Are you worried about any kind of abuse or punishment? Are you worried about her disapproval? Are you worried she might say things that are actually true and sound, but that you don't really want to hear? Talking to her when you say you feel afraid is obviously going to depend on what it is you're afraid of.
• Might you need her help for anything? For instance, it's not often easy, especially outside rural areas, to get sexual healthcare like regular STI screenings you'll need to start getting soon. Or to pay for the pill if you don't have access to a sliding scale sexual health clinic. If not talking to her is also a choice to go without what you need to have sex in a healthy way that also isn't super-risky on a bunch of fronts, that's obviously a big problem.
• How is your relationship with her? This could be a way to keep or get close and really develop the relationship you and your mother have, making it deeper. Leaving her out of this is leaving her out of what will probably be a big part of your life. Or maybe you just don't feel like you have that great a relationship in the first place, like you're very unlikely to connect in this area, or your sex life is just something you want to keep private.
• On a similar note, hiding sex usually doesn't work for very long. Eventually, most people who live at home and hide it from their parents will be found out, and then not only do you have to talk about it, there's also a big damage of trust to deal with, and whatever the consequences of that are.
We can talk more about making this choice, if you like, or anything those suggestions have you thinking about or conflicted with.
