Aiyooo I understand your worry lah, especially first baby! A few of my mum friends went through the same thing, one had a small cyst that the doc said to just monitor, and by second trimester it was gone on its own, so don't panic too much okay. The important thing is your doc is keeping an eye on it from scan to scan, so just follow up as scheduled and try to relax (I know, easier said than done!). But seriously, this is something best discussed with your OB at each checkup so they can reassure you properly based on what they see, especially since sometimes these things do resolve naturally during pregnancy