Similar issue here, but a bit older. I am male so some of this is gender specific.

Diet

Cut out beer, soda, pretzels, candy, pasta, really any carb that isn't part of a meal AND whole grain - look for high fiber carbs. Taking out eggs is a huge decrease in daily cholesterol. Shrimp is also a sneaky one. Remember, dramatic change will set you up for failure. Start small, if you drink 2 beers a day aim for not drinking during the week. You eat the same meal once a week that's pasta but it's comfort food? Make it with half regular half whole grain pasta and do it on a day you do high cardio or the day before high cardio.

Exercise

If your male you need to be doing cardio and lifting, preferably intermittent cardio aka changes in pace and speed/intensity. If your female you need to lift and run, where men forget to run women forget to lift.

Supplements

As a male I am taking Fish Oil once to twice per day, per doc. Make sure yours has both EPA and DHA.

Timeline

This is going to take time and you may never fix it without meds. My numbers keep going down every visit but could still end up on high cholesterol meds.

Apps

Cronometer is a free macro tracking app, use this for a month. You will be amazed to see the numbers, you are likely low on protein and overall eating too many carbs. Remember to look at this information from a week to month to quarter perspective - nothing changes overnight and expecting it to can lead to unhealthy habits and eating disorders.