relapse on day 16... please help (2 things)

Hi Guys,
this is my first post here.

My goal was 14 days nofap. I did it and completed even day 15...And I was so proud of my self for this success.

but before an hour (today, day 16) I thought it would be difficult with continuing with nofap because it was not the plan...
The plan was maximal one time masturbation all 2 weeks when i'm horny).
So i just had a relapse... It was as it were the first time... I'm now 21 and i felt like when i did it when I was 13 or 14.
That's just after 2 weeks NoFap.
I'm sad because of this relapse but more happy because I realized that nofap is the write way. Now my plan is 90 days and then maybe forever.
An another important benefit is that I'm a not anymore very interested in pornos like before, so this is a reason why I want to nofap for 90 days.

I need your help/opinion in 2 things:

1: Should I count again from day 1 (cuz of the relapse) or go on with day 16 (tomorrow)?

2: should I maybe first go on with one time masturbation maximal all 2 weeks (when i'm horny), cuz immediate stop for 90 days may be a too fast decision?

p.s. before the 14 days, i used to masturbate usually 4-5 a week but sometimes daily or 2-3 a day, so maybe it's an addiction that's why 90 days could be a fast decision.

What do you guys think?
thanks for every answer
and sorry for ky english