Witch tampon is better to use as a first timer?

I'm 19 and i have been trying to use tampons since i was 17, my mom used to use Tampax super with the cardboard, When i try to use them i get the feeling of them not being in right. I got a free sample of the u by kotex tampons and they went in easy but i could feel it in my vagina, my mom always told me if it is right i shouldn't be able to feel it at all. Any tips on what i should do or use? Oh and I first started trying to use then while a virgin and i am now not a virgin but i can not remember if i have tried them again or not.. is it true that once you have had sex it is easier to put them in? Please help I'm sick of using pads.