HI and welcome lesbo!

I suggest you tell your therapist about this, that you want to be able to open up and be honest, and you've not been able to in the past. Then he/she can help you with it. This can help you to feel more comfortable about it and might make it easier for you.

And, you don't have to tell everything at once if you don't want to. You can add to something you've already talked about and you can talk about something more than once.

And, if you become uncomfortable talking about something or talking more about something you can stop and say "I am uncomfortable" and then you can talk about feeling uncomfortable. The pace you go is up to you.

Best wishes to you!