Hi guys,
You have all been so helpful to me in the past, and I was wondering if you can tell me if I'm doing the right thing this time around

So, I have been at my job for a bit over 3 months. I work as technician, doing desktop troubleshooting for the most part. Today out IT Director has approached me with the following offer: one of our system administrators has left the company, and the IT director wanted to give me an opportunity to work extra hours overtime as a system administrator doing server maintenance, etc. for about 20hrs a week. I expressed my concern that I don't have enough training for this and that I may not do a satisfactory job but he assured me that I will be trained. Now this is only for a month of May, and after that he wasn't sure but he said he would like me to continue to assist our system administrators in some way.
It sounded really great and happily said that yes, I would love to do it. But here's the thing: we have 2 technicians that are superior to me in status, who have been so good to me and helping with all my questions; they know more than I do and have been here for years. One of them have been working for the company over 10 years. I'm sure they would've loved to have the same opportunity, and I feel undeserving that I am given the chance instead of them.
I just wanted to explain what happened to you guys and ask if I did the right thing by accepting this offer, or if I should go back to the IT director and advise him to consider these other 2 people instead of me.
Thank you so much for your help. I'm really looking forward to your replies.
Thanks!