Age Gap

I(f18) am a college freshman. I matched w a junior (m20) on tinder and him and i have been seeing each other. it’s not a srs relationship but smth rlly casual, low commitment and unlabeled. I’ve finally told a few of my guy and girls friends. One of my guy friends who i’m super close w said it’s weird that i’m with him and that the age gap is too much. He compared it to him being w a junior in high school and asked how I would feel if he was w her , but i said it’s not the same because those are two different stages of life and nothing like what im doing now, but my friend and another girl friend said the guy im seeing and i are also in two diff stages of our lives. They said it’s weird since im fresh out of high school. They don’t know him at all so they don’t understand my dynamic w him. He’s never made me uncomfortable or forced or coerced me to do anything i didnt wanna do. and yes him and i r physical but never fully. i am a virgin and we do stuff but he’s never made me do anything i didnt want to do like i mentioned before and gives aftercare and checks to make sure im okay during. But now it’s making me feel guilty and icky ever since they have shared their opinion and planted a seed of doubt in my mind on this casual relationship i have. I feel bad now and now i’m wondering if i should be w him. my best friend said it’s fine and that im a very logical and guarded person and i need to just trust myself and what i feel is best. She said im so guarded to the point where it’s concerning 😭 is this a concerning age gap? should i not be with him? this doubt never crossed my mind until my friends shared their opinion.