Knitting kids size help

[boredsolicitor]

I'm a novice knitter and am doing a jumper in rowan cotton glacé for a 4 year old . I'm doing the size aged 3-4 and I've just started it and am on the back and it looks a bit big.
The pattern says it's to fit chest size 23 inches /58 cm

The back that I'm doing now is 42 cm wide so I guess that mean when it's finished actual size will be around 80cm allowing for seams etc - does that sound right ? It seems so big compared to chest size?
Any advice welcome

Anyone?

Did you check your tension before you started? If you didn't then you may be knitting looser and need a smaller needle. Depending on the style, some things are to fit a certain size, but are designed to measure bigger.

What does the pattern say is the finished chest size? Most patterns have a "to fit" line and an "actual measurement" line.

Are you using the correct yarn for the pattern and if not are you working to the correct tension? Different yarn from the one recommended may work up significantly different to the sizes on the pattern.

Finally, is the garment supposed to be loose fitting?

Thank you both . Unfortunately the pattern doesn't have an actual size . I might in ravel and do next size down . I'm using the yarn recommended in the pattern .
It's difficult because I think cotton may shrink too when washed - argh!!!

Just spotted a little diagram showing actual sizes as referred to above . The actual is supposed to be 40.5 and I think I'm only a bit over so think I will carry on and try and adjust when I see up the side seams .

I decided in the end to unravel and do a tension square - it's supposed to be 10cm square and mine is 11 wide by 12 long so do you think I should go down a needle size ? Sorry to ask so many questions

I think you should go down a needle size, but start with a tension swatch to check that this gets you closer to the right size. (Disclaimer: I’m no expert - if others advise differently you should listen to them!)

Thank you