Hi Jumper and welcome to the forum.
Firstly I think that, with time and dedication, you will overcome your current experience. A lot of guitarists start off ok then get stuck in a kind of rut that they cannot get out of. In my opinion the reason for this is as follows:
1. When you start playing the guitar you can easily learn to play some chords that sounds like music
2. You can easily see your progress from day to day.
3. As you become more proficient, mastering techniques and playing styles can take a lot longer to accomplish.
4. Your progress is not as easy to monitor as rather than making large progress daily you are making small progress that may not be immediately obvious.
A great example of what I mean is, when you are around a young child growing up you do not notice how much they are growing as you see them everyday. But how often do you hear someone say "haven't they grown" when they have not seen them so regularly?
This is the same with the guitar. You hear yourself everyday so cannot hear your progress, however record yourself and listen back in a months time and you will clearly hear that you have progressed. It is well worth doing.
With regards to tempo and strumming, I would suggest you break it right down and concentrate on getting simple strumming correct. For example get a metronome and strum 4 down strum, one to each beat. When you can do this perfectly try doing 4 downstokes and 4 upstokes alternatively, two to each beat. Then try doing the same but missing one beat out all together.
Practicing this way will quickly teach you how to strum in time with music and you will quickly get to grips with it.
Please feel free to ask for any further help.
Good luck!!
Olly
