Infinite grounding regresses

Suppose, as seems possible, that every day for eternity you will toss a coin and get heads.

Then that you will get heads on every future day seems to be grounded in:

1. You will get heads on day 1, and you will get heads on every day starting with day 2.

And the second conjunct of (1) seems to be grounded in:

2. You will get heads on day 2, and you will get heads on every day starting with day 3.

And the second conjunct of (2) seems to be grounded in:

3. You will get heads on day 3, and you will get heads on every day starting with day 4.

And so on.

So, it seems, infinite propositional grounding regresses are possible.

I suspect that infinite existential grounding regresses are not possible, though.