sucking dick

So I'm 15 and ive given a blowjob to 3 different guys already. I feel like that's bad considering my age but what do you guys think? And also it's hard for me to deep throat because I gag everytime and I've already tried to hold onto my thumb with my dominate hand and it didn't work but I feel like it's a turn off for guys when I gag? I just wanna make sure it's not bad and if you would could you leave some tips?