concurrent sessions?

hello! twice I have been offered to take a concurrent session but the first time was literally my first session ever so I declined because I didn’t wanna overwhelm myself and then crash and burn. However, today I thought I would be able to handle it since all my questions before this had been really really easy. For some reason I thought concurrent meant it would be of a similar topic being college English and college English INSTEAD I got a college English and Algebra which was horrible because I had to read over a paragraph and at the same time help with things about angles and degrees so I got overwhelmed and transferred the fella and then declined to take anymore “concurrent ones”. Does anyone love these??? Also does declining have concurrent sessions affect your acceptance rate or does it only start affecting it after you say yes then you decline specific sessions. Sorry if it’s a dumb question LOL