It's better to try and fail than never try at all.
But since you have very little experience programming in any language, you're going to have to do a lot of learning and you're going to have to get a lot of help.
Objective-C has been around a lot longer; there will be more people available to help and there will be more books, tutorials and example code.
Considering there is a large and valuable legacy code base, it's going to be around for quite some time to come.
Languages aren't that difficult to switch, assuming you're familiar with the paradigm (procedural, object-oriented, functional).
API's are the hard part, but they'll be pretty similar between Objective-C and Swift.
By the time you're proficient with Objective-C, switching to Swift (if necessary) should take just a couple of months at the very worst.