AITAH for not telling a boy I don't like him back because I am scared what people would think

I am F14 and Lukas is same age as me and he super nice and sweet but he get picked on a lot by other kids in our school because he bigger then most of them I dont pick on him and we kinda friends when we 10 but stop after I got new friends which mostly girls and I like him now and I wouldnt mind him being my boyfriend but also I am scared what people think and start bullying me he told me liked me Friday and I told him I like someone else but I dont and I feel bad because he is so kind and I do like him

English is not my first language. Lukas is not his name