I would consider that first jhana yes, not based on your experiences of self etc, but on other things you've said...
Heres my interpretation of 1st jhana,
-in a very naturally concentrated state (on whatever object), as in, no effort needed at all to keep focus on it.
- the state can come out of nowhere , within seconds (often after a short time it feels like you were LOSING concentration), OR over a period of time and slowly.
- Its not necessarily guaranteed you'll be able to hold onto it, but for a few minutes anyway you are very awake, very aware, and very relaxed.
- It simply feels really nice and relaxing, you are completely "in the zone" and not feeling any need to apply effort to stay in the zone.
- thought can arise, but it is very weak, very subtle and very short
Im probably not as experienced at meditation as others here, but thats just my 2c.
Im basing what I said on this:
After a bit, I found I could stop trying to focus on the pressure and let it be without much effort. Sometimes it would seem to move around, but for the most part it stayed pretty localized between my eyebrows. I felt the occasional pleasant tingle along my skin, and a lightness of my body.
This may have been a progression after it, but be mindful not to make presumptions (i.e. the self moving around etc)
The part that really stuck with me as unusual, however, is this: at one point, as I observed this pressure, the darkness of my eyelids (my eyes were closed during all this) seemed to get darker somehow, like it was enveloping me, as if that darkness went beyond just the backs of my eyelids. The best way I can think to explain this was that I experienced myself somehow behind my eyes, inside my skull, like my reference point was no longer my body, but some experience of self inside my body.
But tbh, I dont really understand what may have happened you in the second paragraph.