Really scared of having marfans

So basicly i (m17) have been having an undiagnosed case of pectus excavatum since i was 12 now ( appeared alongside growth spurts that made me go from 5'2" to 6'2" in 2-3 years), the thing seems moderate and hasnt changed all that much throughout time. along with this i had stretch marks on my back, shoulders and thighs which all appeared with my growth spurts and none more since. my wingspan is close to my height but thats as far as it goes for marfan symptoms that dont require going to the doctor (and even then they have good explanations that go out of it). The reason why im saying this is because going to the doctor to have a good diagnosis is near impossible because of the attitude of my parents and because of how it works where i live, making me resolve to ask people online for their opinion on it. Im only looking to be reassured if possible, i already know i dont have one of the cardinal symptoms (recently went to the optologist and my eyes were basicly fully healhty) and i have no family history. I know it just sounds like im trying to get an online diagnosis but its really just that i want to know how to deal with that anxiety and if its justified.