Young and skinny with relatively high LDL

I [25M] had to do a health check for my new job and I was surprised to see some high LDL levels on my blood test. Last time I checked my levels I had normal LDL and a bit high HDL, but now my results are as follow:

Total Cholesterol: 225 mg/dL

LDL Cholesterol: 135 mg/dL

HDL Cholesterol: 84 mg/dL

Hypercholesterolemia runs in my family, my mother and grandmother both have to take pills to deal with it, but I thought that I wouldn't have a higher level until later in life.

I'm fairly skinny (64kg at 1.72m) and I don't think that I have a bad diet. I could probably increase my daily fruit and vegetables intake (which I'm planning to do) but I'm worried that I would start to lose weight, because I have a tendency to do so if I don't eat enough. I do sport at least once a week (I'm also planning to exercise more often) and walk 20+ minutes everyday, so as I said, I'm surprised at the results.

My action plan for the near future is to eat more fruit and vegetables, to try to exercise a bit more, but I wasn't planning on restricting myself from eating what I like (I have a sweet tooth).

Any advice would be appreciated, thanks!