The FBO I learned to fly at sold their 152 right before I took my PPL checkride. I was having the same problem which you're having. I had only flown the 172 four times before my checkride, and luckily I figured it out ON my checkride. My examiner wanted to see me land again, because I wasn't doing too well with them, and this time, just before I started flaring, I put in a throw or two of up trim. Greased it
Try doing that once or twice, see if it works for you.