When you were little, did you ever have an 'imaginary friend' that you would talk to, or play with? Ask you parents if you aren't sure.
I remember I had a few, and I even wrote stories about them in my early 'teen' years. But this is an easy indication of 'Other Dimension Beings'.
Now don't think that every imaginary friend is an angel, in some cases (very, very few) the child's 'friend' turns out to be something it's not. It can even get overly protective of the child, and scare or even try to harm the parents. Don't be afraid though, if a child you know is talking to an imaginary friend. Not all of them are evil, and fewer are mean. If you are a praying person, pray over this experience in the child's life, and pray that they remain safe.
Now, back to Guardian Angels.
Do we all have one?
Yes, we all have at least one.
In my case, I had Seven at one time, with me at all times (possibly eight, but I believe the one I was talking to is my Spirit Guide).
Are they the same as Spirit Guides?
No, Angels and Spirit Guides have clear differences.
Angels were never human, and they never will be. They are (like us) created by The All Father (Some call him God, Allah, The Creator, etc.) but they are also more powerful then humans. That is why they protect us.
Spirit Guides are/were humans, and they have possibly lived before us. They trained for a few hundred years to be paired with their 'human' perfectly. They use their experience to help you, and they take your experience and learn from it. So it's a win-win situation; we both learn from the same experience.
Can I be a Spirit Guide?
Well, as far as I know, yes! In fact, if I get the option when I pass on, I'm going to be one. However, it takes a long time to train for this, anywhere from 300 to 700 years; (as I can't remember my time from Heaven, I can't be sure how long exactly).
Do they Leave us during our life here on earth?
I wouldn't think so. They trained a long time to be paired with us, and it wouldn't make sense in my mind to leave before your time is up.
So we are really protected when it comes to Angels. Your birth sign has an angel, you come with an angel/s when you are born, and there are angels that walk around Earth, only interfering if they are allowed.
It isn't a bad thing to talk to your angels. In fact, it is a very good thing! I will talk to mine every once in a while, thank them for doing a good job keeping me safe, and will just talk with them when I feel lonely.
I would highly recommend trying to talk to your Guardian Angels, but be very precise when you call to them. Make sure you make it clear that you want to talk to YOUR guardian angel.
P.S. Angels will never hurt, trick, deceive, or lie to you. They don't sin. So you can trust them. Just get to know them first.