Can you take the new pack of pill for one week then take your placebo pills?

Question

Ok so I've been on birth control for 4 months and I take them every night on time and it's all good. Usually by my second placebo pill I get my period. So today I noticed that tomorrow is my last active pill and then I have to take the placebo pill (which means In 3 days ill get my period) but the app says I should get my period in 5 days. I'm planning on swimming and being with my bf on Monday (in 3 days) and I really don't want to be on my period I have been planning t for three weeks. So can I start the new pack but only take one week then the placebo pills? I don't want my parents to be suspicious on why I haven't gotten my period in a month cause they'll worry and they won't understand how the active pills work. So I need opinion/advice. Today's Friday and I'm having plans on Monday do u think I'll get my period? 
PS : today I turn 16 :)

Answer

I wouldn't. The active pills should be taken the full 21 days so either skip your period by skipping the placebos and going straight to the active pills in the next pack (take the full pack, not only 7 days worth) or have your period on time.