I haven't truly liked someone in years
Has something happened recently that made you realize that?
People can talk about love life all day long
Relationships can be a big part of most people's life but it is okay not to be in a relationship. Not everybody has to be in one and you can be happy without one.
It sucks since I'll never date a hot teen again. I won't get married for sure.
It's fine that you don't want to be in a relationship right now, so don't worry about it.  However, you shouldn't be so pessimistic either.  You never know who you might meet later in life, so keep your options open, and be receptive to potential partners.