first of all we are talking about 4.5 KIDS, not adults, adults are much stronger and more developed, so a 4.5 adult would and should beat a 4.5 kid. But their skill level and technique would be about the same!! and stop posting vids and links of 5.5's and 6.0's, i was talking about how 4.0-4.5 isnt amazing for a 14 year old. and yeah theres no way a 4.0 cud beat a 5.5, so stop posting vids of 5.5 6.0 players!!!!!!
I forgot to mention that you can't reciveve NTRP rating until your 18 (90% sure thats how it works). Ranking system for juniors is different. If a 14 year old "4.5" has the same technique of an adult 4.5, that doesn't matter too much. If their footwork is terrible and they're mentally unstable (which is often the case for 14 year olds), then they cant compete at that level. That's IF they have the same technique. 4.5 is damn good, and you would be one hell of a tennis player if your playing that level at such a young age!