Date order question

As you are plotting strings, you could put a space character in front of
the December dates so that they are first.
date<-c(" 12-29"," 12-30","01-01")
That fixes the problem in this example. You can order all the dates by
putting more spaces in front of earlier years. That will get messy.

Put the year in front +/- apply as.Date() and you would be fine...

date<-c("2022-12-29","2022-12-30","2023-01-01") |> as.Date()

It may be that the source data doesn't have a year and the example given is
to show us dummy data.  You could 'automate' the addition along the lines
of:

require(tidyverse)
#if you have up to date Tidyverse this includes lubridate
current_date <- sys.Date()
current_month <- month(current_date)
current_year <- year(current_date)
date<-c("12-29","12-30","01-01")
PT <- c(.106,.130,.121)
data <- data.frame(date,PT)
data |>
  # separate the date into month and day column
  separate (date, c("Month", "Day"), sep="-") |>
  # add a year if month is > current month must be last year
 mutate (year = if_else(Month > current_month, current_year - 1,
current_year)) |>
  #rebuild the date
  unite (date, c("Year", "Month", "Day"), sep="-") |>
  mutate(date = as.Date(date)) -> data

If you don't want year on the axis of the graph, that should be dealt with
in ggplot not in the data carpentry