Sadly I must say that I am yet to meet someone who made a decent cheddar with her kit. She is giving you a Ricotta mould, mystery cultures and instructions that don't stress the importance of acidification schedule which is the most sensitive thing for Cheddar making.
- Sounds like too much acidity to me. Don't over-dose culture, rennet or calcium. Cheese is more likely to fail if you put too much than if you put too little.
- Be very vigilant about temperatures and timed processes. It's the key to getting the cheese texture and acidity under control
- Press - use it with a proper cheddar, Gouda or Manchego mould, something for hard cheese with just a few weeping holes and preferably cheesecloth.
- 1 months is not enough time to age for Cheddar. There are far too many biological processes that need to take place in sequence for it to be done at 1 month. I personally wouldn't even open it at 2 months.
- milk, you don't need to use raw milk, but you should definitely use non-homogenized (creamline) milk
I don't think Cheddar would be hard to practice and figure out so don't get discouraged. It takes a bit of practice. I do however suspect that it's not a fun cheese to start with because you are full of anticipation and then have to wait months to see the results, and by the time you see it, you don't remember what you did right or wrong. Usually the first few cheeses can have issues like you mentioned. (you are not alone!). I would try cheeses that have a shorter maturation cycle first. It will give you a chance to do a few rounds by the time it takes aging one cheddar. They are generally more successful early on and you will taste it fast enough to remember what you did and how it was better than the time before. It will give you energy and happiness that will take you through parallel experimenting in perfecting cheddar and other long aged cheeses on the side at the same time.