Hi @Amonda! Glad you got things working. 
As a general hint, new versions of R currently get released every year around April (this year's R was 3.6). There are usually a handful of minor "patch" releases in between major versions (e.g., 3.6.1, 3.6.2, etc), but these don't count as a "new version".
Once you are more than 1 version behind the current version, it will start to get much harder to install packages because of dependency problems like you encountered, and also because pre-compiled package binaries will no longer be available (package binaries for Windows and Mac are generated only for the latest version of R and the one before that). So unless you have a specific reason for running an older version of R (and the system administration knowledge or support to take on the challenges), it's usually a good idea to keep R up to date.