I am sorry that your t is going on maternity. It must be very hard to accept that. I find it hard to accept t has a family and is not a therapist 24/7 let alone have a baby.
I think it's important to do what you feel is right for you on your last session. I imagine your t was trying to keep the last session light as she can't support you if anything big comes up after Friday but it's your last session so please use it how you want to!
As for a present I would absolutely think it would be ok and it's a lovely thoughtful gesture for you to think of

Sent from my iPhone using Tapatalk