I am surprised you even had to ask the question.
If you want to know ask her.
If she is she will tell you if not she will tell you.
Being 24 you should know how to ask women questions.

Years ago when I was an active gainer I would have dreams occasionally where I would be much larger.
Had a few dreams where I ate lots of Ice cream and gained a bunch of weight with in 20 min or so.
A few times I dreamed I woke up 100 lbs heavier and had no clothes to wear to work.

You are only 20 years old you have all the time in the world to figure it all out.
There is no reason to say if you are straight or gay that doesn't really have anything to do with anything.

Never felt the need to talk to a therapist about anything.
I don't care what people think about what I may be into. Its none of their business.

Yes and especially by my eventually ex husband and my Mother.

If you feel so compelled to tell her thats up to you but if she has a fit and hates you for saying it then that shows you should have kept your mouth shut.
Just keep quiet and tell her how great she looks as she puts on a few pounds.
Never make it about her size make it all about her.

Lots of truth to that I lost a few times after gaining lots of weight and the last time I regained the weight I gained more in my belly and it was a lot flabbier.
If you really want to gain then whats stopping you? Why wait? Start now and see what happens.

Just let it happen that way you don't have to tell her anything right now.
You young people are always making things harder than they need to be.LOL

Sounds to me that you are unsure what you really want to do.

Couple of inches but I have to pull the seat up to drive because I'm short