So, I was wondering what you guys do recommend. In the moment, I am the only user and the only admin on the same time on the mac. But, from a admin/security perspective, there should be already a different account for me as a user and another one for the admin, no?
Only in certain specific situations would want to separate your user and admin accounts in any UNIX system (and most of those situations are for policy or legal reasons not operations safety).
Worth pointing out here that this is an admin account capable of privilege escalation to carry out-root-like functions - not the unix 'root' account, which is a bad idea to log in as unless you need to, since any mistakes there (such as accidentally deleting the entire filesystem) have repercussions. (The root account has to be explicitly enabled on Mac OS X.)
So, no, I do not see any reason to create multiple separate accounts for performing different roles on your computer.
On other unix boxes, you may well need to create something non-root, where you'd do admin tasks by either sudo'ing (if available) or by deliberately logging in as root first.