Please help - date parse error (a very simple dd-mm-yyyy) csv to logstash

my CSV has the following:
gymid,gymdate,sets,exercise,worktime,rest,reps,weight,muclegroup
3013,20-03-2020,1,Barbell Deadlift,01.42,03.02,11,47,back

my config has:

input
{

file{
    path=>"D:/gym1.csv"
    start_position=>"beginning"
    sincedb_path=> "NUL"
}

}

filter
{
csv {
separator=>","
columns=> ["gymid","gymdate", "sets", "exercise", "worktime", "rest", "reps", "weight", "musclegroup"]

}

date {

match => ["gymdate", "dd-mm-yyyy"]

target => "@timestamp"

}

mutate {convert => ["sets", "integer"]}

mutate {convert => ["reps", "integer"]}

mutate {convert => ["worktime", "float"]}

mutate {convert => ["rest", "float"]}

mutate {convert => ["reps", "float"]}

mutate {convert => ["weight", "integer"]}

}

output

{

elasticsearch{

hosts=> "localhost:9200"

index=>"gym"

document_type => "workout"

}

stdout{}

}

i get dateparseerror

Month should be MM, not mm, although I am surprised you get an error for that.

thanks a ton this solved the problem. i saw different behaviours each time. Once it did not give me error but simply take it as a string and when sometimes the error that came up. Also until the time i used the timezone of UTC, the date kept showing some other values
thank you for helping.