Will a crime caution effect me getting into university?

[Anna]

2 Years ago (I was 13) I was with 2 girls. This 2 girls always bullied me if I did not do what they asked, and had a lot of influence over other girls at the school. I tried to get away from them many times but I was left so badly bullied I didn't eat for 4 days and didn't bother going school. So when they asked me to go to this village with them one day, I went. The day wasn't too bad, I didn't say much, but they didn't either. Until we went to a shop and they told me to steal a bottle of wine. I didn't know what to do and I was so scared, I didn't really think and nobody was looking, and I didn't think of the consequences of getting caught, I thought of the consequences of not doing what they said. I ran and didn't get caught, until 2 hours later when a police woman saw my 'friend' who matched the description given. I owned up and I apologized to the shop keeper, and he was very nice and let me off with a caution.
I am now 15, and I have got away from them girls after a lot of hard work, and luckily I'm not in any of their classes or any one they know classes anymore. I go to a really good school and I get all A*, and everyone has really high hopes for me at GCSE. I have learn't from my mistakes, and actually that is one of the main reasons why I tried so hard at school and got where I am now.
I got a lot of bullying for it, one time I even got repeatedly hit by a boy because I didn't want to talk about it, but that's over now.
All I'm wondering, is how will this effect me in the future? Will I be able to get into sixth form/university? and what about a job?
I'm mainly worried about sixth form and university at the moment, I can worry in the future about a job.
It was only a caution, but will sixth forms look into that? I know my sixth form looks at people who have posted stuff about it on Twitter. And what about university? Like maybe Oxford or Cambridge?
Also if you could answer this:
A guy managed to take a photo of me in the police car, and put it on facebook. He is 2 years older than me and very intimidating. I used to have him as a friend on facebook, but after I saw the comments I got on that photo (they were very bad) I deleted him. I went back recently to look for the photo, but I couldn't find it. I don't have him as a friend anymore, and there is a possibility that it's still there but I can't view it because he is not my friend. I don't want to ask any of my friends about it, because I think they have finally forgotten about it, and I don't want to ask him or add him as a friend because he really scares me. I was just wondering if the school will find this? or the university? and how this will effect me
Thank you for helping me, it really means a lot

[Scott Wimer]

When you turn 18 as long as you have no federal offenses (felonies) your record is expunged. And regardless colleges do not look at criminal history I believe, other than sex offenders on or near campus however.

[Phantomfeather279]

No that's a minor offence.

[Lynda]

No I really wouldn't worry cuz it was just a warning with no charges and if you can not find the photo it must have been taken off -

[jimbo]

Lets be very clear about this because it makes a world of difference. If the police lady cautioned you, that is to all intents and purposes a sentence and will be on your juvenile record. If the shopkeeper told you off and gave you a caution to behave yourself in the future, then you have nothing to worry about, well perhaps you should because you did steal after all, but if it was him you will not have a record. It is highly unlikely that this incident will keep you out of university, but just make sure you have learned your lesson.

[Kernow Lady]

A minor crime at 13 will not stop you from getting into a UK Uni. 6th forms at school do not do CRB checks. No one is interested in facebook.
UK