The biggest thing I wish I’d know when I was 20 is that you deserve to be loved for who you are as a whole person, not despite it. And that is particularly true for trans and nonbinary people.
Don’t settle for someone who only loves a part of you. Don’t relegate yourself to people who only like your assigned gender. There are people out there who can and will love you for the complexity of who you are and who you are becoming. And yes, nothing is guaranteed to be permanent, but the biggest gift is finding someone that doesn’t expect you to be static but relishes the ways you grow and change.
For nonbinary people, sometimes that means not dating monosexuals like straight people or gays and lesbians. There is a whole big wide world out there of queers and pansexuals and bisexuals and more who don’t expect you to have a particular set of matching body parts and gender expressions.
You deserve to be loved for your gender, not despite it.