If you feel relief and a joy with that relief which gives you rapture and a warm vibrating pleasure then I think it would be the first jhana. It's like making meditation time a time to let go of all objects to chase and just stay with one object. It's almost like doing a complicated job and then only having to do a simple job to the point you feel relief. I remember when I got my first jhana I definitely talked in my mind and got distracted because there's no better proof than actual experience.
Try to look at your concentration practice as a way to let go of all thoughts and relish in the seclusion of just one object. When you relax in this and have enough jhana experiences you should be able to let go of the meditation object and then move it to a nimitta (brightening of the retina) or just use the enjoyable body sensations as an object to then just stay with the object without a need for much sustaining. Because of the enjoyment there is no need to keep sustaining it. At this point you would get to the 2nd jhana and that feels smooth and blissful and less agitating than the 1st jhana. It happened to me when my brain got used to the first jhana and moved to the 2nd. The more refined and less exciting the jhana the more restful and peaceful it becomes. It's like the brain goes crazy with novelty and then it lets go of attachment to what it knows too well.
Leigh Brasington has good instructions:
Leigh Brasington - Instruction for Entering JhanaOnce you get to the 1st jhana you can start looking at the 3 characteristics as Fivebells describes.