I would agree with the others but personally, I wouldn't wait 12 months just because people told me to wait 12 months iykwim? If your cycle is in any way irregular, you are over 32 (fertility rates actually start to decline at 32) or you have any other reason to suspect that something could be up, my advice would be to get checked out sooner rather than later. A few simple blood tests to check your hormone levels and ovulation is a good place to start and it doesn't do any harm to have them done early...
...Four months really isn't a long time hun and it's far more likely than not that you'll be pregnant very soon, but I've also seen people wait 12 months only to be told they should have seen someone much earlier. When you want a baby badly enough, 12 months is a very, very long time.
The OP is only 27 so it's not like her clock is ticking. No need to clog up the waiting lists for people who have fertility problems.

FWIW, you should try for 12mths under 36 & 6 mths over 36.

OP, if your cycles are regularly around 37 dyas (doesn't look like you've updated your chart), then they are still classed as regular cycles. Give it another 6mths or so charting & I bet you'll have your BFP.