[JandE]

This will be my first time taking a plane on my own and I want to make sure I'm not going to get turned away also for having a one way ticket, would it be better to get a return?

I have heard of people on one way tickets sometimes having difficulties.

I have being refused boarding myself for not having a return ticket, and had to buy an expensive ticket at the airport, there and then, to catch the flight.

Consequently I always get a return/outward ticket, but the cheapest one I can find, as I rarely used them.
I now refer to them as throw away tickets. I have had a few, they cost money, but save anxiety.

For you, if they feel you may not be intending to leave, they may not allow you in, especially if you mention marriage.