When I meet someone new, I definitely start with small steps to see if this is someone that I can see a relationship developing with. I like the advice I was once given- I don't have to trust the person when I first meet them. Trust is something to work up to.
I might go for a walk with someone in a public place or out to eat. I might message with them a little about the general things like favorites (places, color, books, etc). Then, I can decide after each encounter if I want to meet with or chat with them again. I can keep reminding myself that I am an adult now and have ways of protecting myself if I sense anything that triggers me with this current relationship. That helps.
Also, I like to be aware of when I say things in absolute like always, never, nobody, everyone, etc. Because chances are this is a cognitive distortion. And I can challenge it.
"I have nobody" might turn into- "I have my therapist." "I have my pets." "I have my best friend." "I have this online friend." or "If I am cautious, it is possible that I could have at least one person in my life."
"I can't trust anyone." might be challenged with "I don't have to trust everyone with everything. I can take it in small steps to see if they earn my trust." or "I may not trust people fully, but I mostly trust (insert name)."
"Everyone in my life has hurt me." might be challenged with "I know that hurt is a part of life, but when I reflect there are people who have not hurt me in a major way." or "My sister never hurt me."
When I come up with at least one challenge to these statements, it helps me remember that I amy feel like it is always, never, everyone, but maybe it isn't or maybe there is a way I can see it changing.