I couldn't thread a sewing machine until a couple of years ago, but very quickly wanted some extra features that my sale bought machine didn't have, such as being able to stop the machine at the end of sewing with needle down, an auto lock button which (sometimes) saves you reverse stitching and a built in thread cutter - the thread cutter has paid for itself in the amount of saved thread, lol.
I suggest you buy an inexpensive used machine to start with and look for these features if you decide to upgrade later. More expensive quilting machines have loads more features again.
Ideally you should be able to drop your feed dogs (the little toothed cogs that feed your fabric through) and a needle threader is great too.