Dumb question, but help me understand?

So I’m thinking of buying crypto in this dip in the market (dunno if that’s dumb or not, just trying it). The thing that I’m wondering is: let’s say I bought like $10 of bitcoin ~hypothetical~ and that gave me (whatever), like 0.00000000001 bitcoin. If the value kept going down, and I ended up with like $0.01 of bitcoin, I would still own that 0.00000000001 of bitcoin, right? So if the value went back up, I would still have whatever money that ends up being worth, right? My concern is that, if I put some money into it (and it won’t be a lot), then it could end up deflating to a fraction of a cent, and Coinbase will say “You don’t own any money’s worth of bitcoin,” and I will be out.

Please let me know if this question makes any sense at all, and any help would be appreciated. Please be nice too, I’m trying to learn about this stuff for the first time.